Your assistant is leaving two voicemail messages because at first It's generating a message An actual message using the user input and then After sometime it identifies that it's a voicemail and then it leaves out the voicemail message So what you need to do here is set your first message mode To assistant wait for the user and configure your Twilio Voicemail Reduction Parameter accordingl to your call After that it will leave only the voicemail message if it's a voicemail. Let me know how it goes for you.