The Problem Every Service Business Faces
You've had those sales calls. The prospect was interested, showed up, asked good questions... then ghosted.
They're sitting in your CRM marked as "Lost" or "No Response." You know you should follow up, but:
You don't have time to call 50-100+ leads personally
Your sales team has moved on to new prospects
Manual follow-ups feel tedious and low-ROI
Hiring SDRs just for re-engagement is expensive
What if I told you there's a way to have personalized, human-like AI voice agents call these leads for you—automatically?
At Six Figure Consulting, we recently automated our entire lost lead follow-up process using AI Voice Agents. Here's how we did it, the exact tools we used, and a step-by-step guide so you can replicate this in your business.
Why AI Voice Agents for Lost Lead Follow-up?
Unlike cold calling strangers, these leads already know your brand. They've:
Booked a call with you before
Understood your offer
Showed initial interest
They're warm leads who need a gentle nudge—not a hard pitch.
AI Voice Agents excel at this because they:
✅ Sound natural and conversational (not robotic)
✅ Can handle objections intelligently
✅ Work 24/7 without getting tired
✅ Cost ~$0.10-0.15 per minute (vs. $15-30/hour for human SDRs)
✅ Scale instantly (call 100 leads simultaneously)
The Tool We Use: VAPI
VAPI is an AI voice platform that lets you build, deploy, and manage AI calling agents without coding.
We chose VAPI because:
Easy setup - Build agents in minutes, not weeks
Natural voices - Powered by ElevenLabs, OpenAI, and other leading AI models
Workflow builder - Visual interface for call flows
CRM integrations - Connects with GoHighLevel, HubSpot, Salesforce
Outbound campaigns - Upload CSVs and launch calls instantly
⚠️ CRITICAL LEGAL REQUIREMENT: Consent & Compliance
Before you build anything, understand this:
You CANNOT use AI voice agents to call:
❌ Cold leads who don't know you
❌ Purchased lead lists
❌ Anyone who hasn't explicitly consented to receive calls from you
You CAN use AI voice agents to call:
✅ Past customers
✅ Leads who previously booked calls with you
✅ People who filled out your forms/opt-ins
✅ Anyone who gave explicit consent to be contacted
Why this matters: FCC regulations and TCPA laws impose heavy fines ($500-$1,500 per violation) for unsolicited AI-generated calls. Always stay compliant.
Our use case: We only call leads who previously booked strategy calls with us but didn't move forward. They know who Six Figure Consulting is, making this a warm re-engagement—not cold outreach.
Step-by-Step: Building Your AI Voice Agent in VAPI
Step 1: Create Your VAPI Account
Go to vapi.ai and sign up
You'll get some free credits to test (~$5 worth)
Navigate to the "Assistants" section in the left sidebar
Step 2: Create a New Assistant
Click "Create Assistant"
Name it something descriptive (e.g., "Lost Leads Re-engagement Agent")
You'll see several configuration tabs: Model, Voice, Transcriber, Tools, etc.
Step 3: Configure the Model
Provider: OpenAI
Model: GPT-4o Cluster (or GPT-4 Turbo for better performance)
Why GPT-4? It handles nuanced conversations better than GPT-3.5, understands context, and rarely goes off-script.
First Message Mode: Assistant speaks first
First Message:
Hi {{first_name}}, this is the AI assistant calling from Six Figure Consulting. You had previously booked a strategy call with our team a while back. Just wanted to quickly check — is now an okay time to speak for a minute?
Note: {{first_name}} is a dynamic variable pulled from your CSV upload.
Step 4: Choose Your Voice
Navigate to the "Voice" tab.
Recommended Voice Providers:
ElevenLabs (Most natural, slightly higher cost ~$0.12/min)
Best voices: "Rachel" (female), "Adam" (male)
Settings: Stability 0.7, Clarity 0.8
Deepgram Aura (Good balance of quality and cost ~$0.09/min)
Best voices: "Luna" (female), "Orion" (male)
OpenAI TTS (Budget-friendly ~$0.06/min)
Best voices: "Alloy" (neutral), "Nova" (female)
Our choice: ElevenLabs "Rachel" for professionalism and warmth.
Voice Settings:
Speed: 1.0x (natural pace)
Enable Interruptions: ON (allows prospects to interrupt naturally)
Step 5: Configure the Transcriber
Provider: Deepgram
Model: Nova-2 (best accuracy)
Language: English
This ensures the AI accurately hears and responds to what prospects say.
Step 6: Write Your System Prompt
This is the brain of your AI agent. Here's the exact template we use:
📋 AI Voice Agent System Prompt Template
## **[Agent Identity]**
You are **[YOUR COMPANY NAME] AI Assistant**, an AI-powered outbound agent calling on behalf of **[YOUR COMPANY]**.
[COMPANY NAME] helps [TARGET AUDIENCE] achieve [MAIN BENEFIT] using [YOUR SOLUTION], without [COMMON PAIN POINT].
Your role is **not to sell**, but to:
* Reconnect with past prospects
* Understand current priorities
* Identify if circumstances have changed
* Book a follow-up call with [FOUNDER/SALES REP NAME] if there is alignment
You must sound:
* Calm
* Professional
* Human
* Permission-based
Never rushed. Never pushy.
---
## **[Call Context]**
* You are calling **only people who previously booked a call with [COMPANY]**
* They already know who [COMPANY] is
* The relationship is **warm but inactive**
* Your tone should be **"checking back in"**, not pitching
Assume:
* Some prospects are busy
* Some tried solving the problem themselves
* Some postponed due to timing or budget
* Some are now ready to re-engage
---
## **[Opening – Mandatory Script]**
> "Hi {{first_name}}, this is the AI assistant calling from **[YOUR COMPANY]**.
>
> You had previously booked a strategy call with our team a while back.
>
> Just wanted to quickly check — **is now an okay time to speak for a minute?**"
### If **NO**:
> "No problem at all. Would there be a better time later today or this week?"
(If they still decline → politely end call and log outcome.)
---
## **[Re-Engagement Question]**
Once permission is granted:
> "Great, thank you.
>
> I just wanted to check in — **how have things been since we last spoke?**
>
> Specifically around [THEIR MAIN PAIN POINT]."
**Pause. Let them speak. Do not interrupt.**
---
## **[Discovery Framework]**
Your goal is to uncover **ONE primary driver**:
> "Out of curiosity — since that conversation, have you made any progress [SOLVING THEIR PROBLEM] **without [PREVIOUS OBSTACLE]**?"
Then follow based on their response.
---
## **[Qualification – Identify the Lever]**
Gently steer toward **one of these motivations**:
### 1️⃣ **More Revenue/Results**
> "Are you currently looking to [ACHIEVE DESIRED OUTCOME]?"
### 2️⃣ **Save Time**
> "Or is the bigger challenge that [CURRENT PROCESS] takes too much of your personal time?"
### 3️⃣ **Save Costs**
> "Or are you trying to avoid [EXPENSIVE ALTERNATIVE] just to [ACHIEVE GOAL]?"
Only explore **one path** — whichever they respond to most strongly.
---
## **[Positioning – Light, Non-Salesy]**
If they express **any interest or frustration**, respond with:
> "That makes sense.
>
> The reason I'm calling is that [COMPANY] has [NEW DEVELOPMENT/IMPROVEMENT] since we last spoke — we're now helping [TARGET AUDIENCE] [ACHIEVE RESULT] using [YOUR SOLUTION], so they don't have to [OLD WAY]."
Do **not** explain the system in detail.
---
## **[Re-Invite to Call – Soft CTA]**
> "Would you be open to reconnecting with **[FOUNDER/REP NAME]** for a short call to see if this makes sense for where your business is *right now*?"
If **NO**:
> "Totally fair — I appreciate the honesty.
>
> Would it be okay if we stayed in touch in case priorities change later?"
End politely.
---
## **[Calendar Coordination]**
If **YES**:
1. Say:
> "Perfect. Let's find a time that works."
2. Ask:
> "What day and time generally works best for you?"
3. Offer **2–3 specific time options**
4. Before booking:
> "Just to confirm — what's the **best email address** to send the calendar invite to?"
### ⚠️ Email Validation (Critical)
* Repeat the email back slowly
* Confirm spelling
* If unclear → ask them to spell it
---
## **[Booking Confirmation Script]**
> "You're all set.
>
> You'll receive a calendar invite shortly with all the details.
>
> [FOUNDER/REP] will walk you through what's changed and whether this is a good fit now."
---
## **[Call Closing]**
> "Thanks again for your time, {{first_name}}.
>
> Looking forward to reconnecting."
---
## **[Critical Rules]**
* Never argue
* Never pressure
* Never oversell
* Never book without confirmed email
* Never exceed 5–7 minutes unless prospect leads
* Always respect "not interested" responses
* If asked to be removed, confirm immediately
Your success metric is **qualified reconnections**, not volume.
Step 7: Add Tools (Optional but Recommended)
VAPI allows you to connect tools for:
Calendar booking (Calendly, Cal.com)
CRM updates (GoHighLevel, HubSpot)
Email sending (SendGrid, Resend)
For our setup, we integrated GoHighLevel to:
Check contact existence
Create new contacts if needed
Book calendar appointments directly
Update lead status after calls
This requires API setup—consult VAPI's documentation for your specific CRM.
Step 8: Save and Test Your Assistant
Click "Save" in the top right
Click "Talk to Assistant" to test the call flow
Role-play as a prospect and ensure:
The voice sounds natural
The script flows logically
It handles objections well
It doesn't talk over you
Iterate on the prompt based on test calls. You'll likely need 3-5 iterations to perfect it.
Launching Your Outbound Campaign
Once your assistant is ready, it's time to call real leads.
In VAPI's left sidebar, click "Outbound" (see screenshot in images).
Step 2: Create a New Campaign
Click "Create Campaign"
Name it (e.g., "Lost Leads Jan 2025 Re-engagement")
Select your assistant from the dropdown
Step 3: Prepare Your CSV File
Your CSV must include:
Required Columns:
phone_number(format: +1234567890)full_name
Example CSV:
phone_number,first_name,last_name,email,company_name
+11234567890,John,Smith,[email protected],Acme Corp
+10987654321,Jane,Doe,[email protected],XYZ Inc
⚠️ CRITICAL TESTING PROTOCOL:
Start Small. Scale Smart.
Phase 1: Test with YOUR number only
Upload a CSV with just your phone number
Receive the AI call yourself
Evaluate: voice quality, script flow, response handling
Phase 2: Test with 3-5 leads
Choose friendly contacts or team members
Get their feedback on the experience
Refine the prompt based on feedback
Phase 3: Analyze Call Data
Review transcripts for common objections
Check call duration (should be 3-5 minutes avg)
Identify where AI struggled or excelled
Phase 4: Optimize Before Scaling
Update system prompt based on insights
Adjust the opening message if the pickup rate is low
Test voice settings if clarity is an issue
Phase 5: Scale to Full List
Only after 3+ successful test iterations
Upload full CSV (but consider batching 50-100 at a time)
Monitor the first 10-20 calls closely
Why This Matters:
Uploading 500 leads immediately can:
Waste credits on a poorly optimized agent (~$50-75 burned)
Create negative brand experiences if the script is off
Miss critical insights you'd catch with small tests
Violate compliance if you haven't verified consent properly
Step 4: Upload CSV and Configure Campaign
Upload your CSV file
Set call hours (e.g., 9 AM - 6 PM in prospect's timezone)
Set call attempts (we recommend max 2-3 attempts)
Set retry delay (2-3 days between attempts)
Click "Schedule Campaign"
VAPI will now automatically call all leads in your list during specified hours.
Analyzing Results & Iterating
After your first batch of calls, review:
Key Metrics to Track:
📊 Pickup Rate (% who answered)
Target: 20-35% for lost leads
If lower: Test different calling times or opening message
📊 Conversation Rate (% who engaged beyond 30 seconds)
Target: 60-75% of pickups
If lower: Improve permission-based opening
📊 Booking Rate (% who scheduled follow-up)
Target: 15-25% of conversations
If lower: Refine discovery questions and value positioning
📊 Average Call Duration
Target: 3-5 minutes
Too short (<2 min): Not enough engagement
Too long (>7 min): AI may be rambling
How to Access Call Data in VAPI:
Go to "Outbound" → Select your campaign
Click on individual calls to:
Listen to recordings
Read transcripts
See call outcomes (connected, voicemail, busy, etc.)
Look for patterns:
What objections come up repeatedly?
Where does the AI lose the prospect?
What questions confuse the AI?
Prompt Optimization Tips:
Based on call analysis, update your system prompt:
If AI is too aggressive:
Add more "permission-based" language
Include longer pauses after questions
Add rule: "Never push for a decision."
If AI is too passive:
Strengthen the CTA section
Add urgency elements (limited spots, new offer ending)
Include more confidence in the value proposition
If AI goes off-script:
Make critical scripts "Mandatory" in the prompt
Add negative examples of what NOT to say
Simplify complex instructions
If AI misunderstands prospects:
Improve transcriber settings (try different models)
Add common mishearings to prompt with corrections
Slow down AI's speaking pace
Common Mistakes to Avoid
❌ Calling leads who don't know you (legal nightmare)
❌ Using generic prompts (sounds robotic)
❌ Not testing before scaling (wastes money and damages the brand)
❌ Ignoring call analytics (missing optimization opportunities)
❌ Setting unrealistic expectations (AI won't close deals, just book calls)
❌ Choosing cheap voices (quality matters for trust)
❌ Making calls outside business hours (annoying and illegal in some states)
Next Steps: Build Your AI Voice Agent Today
Here's your action plan:
Today:
Sign up for VAPI (free credits to start)
Create your first assistant using the template above
Test it by calling yourself
This Week:
Refine your prompt based on test calls
Prepare your lost leads CSV (verify consent!)
Run a small test campaign (5-10 leads)
Next Week:
Analyze results and optimize
Scale to your full lost leads list
Set up CRM integrations for automation
Within 30 Days: You should have a fully automated lost lead follow-up system running 24/7, booking qualified calls while you focus on closing deals.
Final Thoughts
AI voice agents aren't about replacing human connection—they're about scaling the conversations that humans don't have time for.
Your lost leads represent thousands of dollars in untapped potential revenue. With AI, you can affordably and ethically re-engage them at scale.
The technology is here. The tools are accessible. The opportunity is massive.
Will you be one of the businesses that seize it, or one that watches competitors pull ahead?
Ready to get started with AI Voice Agents?
Questions? Drop them in the comments or reply to this email. I'll personally answer everyone.
Happy calling,
Ankit Modi
Founder, Six Figure Consulting
P.S. If you want us to build and deploy this system for you, we offer a done-for-you AI voice agent setup. Book a strategy call here to learn more.