Can I disable voicemail in Talk?
Unfortunately, at this time it is not possible to disable voicemail altogether. Please refer to our Product feedback forum if you would like to vote for this functionality and share your use case in the discussion. I'd also recommend subscribing to the article so you'll be updated with any further comments.
That being said, the best workaround would be to record a greeting for voicemail advising that there aren't any agents available to take the call, you should then leave around 2-5 minutes of silence at the end. The 2-5 minutes of silence will most likely mean that the end user will not reach the beep to leave a message and no voicemail message will be recorded.