Intelligent Voice PCI redaction for Zendesk does not scan voicemails by default, only inbound and outbound calls.
If you have payment card data in voicemails you can enable scanning of voicemails by following these steps:
1. Add a new trigger for voicemails. You can copy the trigger included in the Intelligent Voice PCI redaction application. For more information on triggers see About triggers and how they work.
2. Turn off Zendesk built-in transcription of voicemails. See Configuring voicemail options for instructions.