Request for Fee Waiver Due to Spam Calls on Voice Agent

Support Help
1

Hi Retell Team, @Omar_Ashraf

We wanted to bring an issue to your attention regarding a few recent calls made through our voice agent. If you notice the last several call logs, the caller appears to have repeatedly spam-called the agent, with multiple calls reaching the maximum call duration.

Because of this repeated spam activity, these calls were still billed to our account, even though they were not genuine or intentional interactions on our end. We’ve also since taken steps to mitigate this from our side.

Given that these charges were incurred due to spam calls rather than legitimate usage, we wanted to kindly ask if it would be possible to waive or credit the associated fees for those calls.

Happy to share any additional details, timestamps, or call IDs if needed.

Thanks in advance for your understanding and support - we really appreciate it.

Best regards,

2

I understand your concern about spam calls generating costs. Based on available information, here are protective measures you can implement to prevent future spam attacks:

Spam Protection Strategies:

  1. Inbound Webhook Filtering - Enable an inbound webhook on your number, check the from_number, and reject suspicious calls by responding with a 200 status without including override_agent_id(1)

  2. Agent-Level Detection - Add logic in your agent’s prompt to detect repeated or bot-like audio patterns and instruct the agent to hang up quickly(1)

  3. Abuse Prevention Best Practices:

    • Rate limit by phone number or IP address
    • Use user identification when possible
    • For public widgets, enable reCAPTCHA v3(1)

  4. Call Duration Limits - You can configure max_call_duration_ms on your agent to prevent calls from reaching excessive lengths. The minimum value allowed is 60,000 ms (1 min), and the maximum is 7,200,000 ms (2 hours), with a default of 3,600,000 ms (1 hour)(2)

  5. Silence Detection - Configure end_call_after_silence_ms to automatically end calls after periods of inactivity. The minimum value is 10,000 ms (10 s), with a default of 600,000 ms (10 min)(2)

Important Note: Retell AI doesn’t currently auto-detect prerecorded or bot audio, so most mitigation needs to be implemented via webhooks, SIP provider rules, or agent logic(1)

For billing disputes related to spam calls, I recommend reaching out directly through these support channels:

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