My Google Fu is failing me. I am trying to upload a WAV voicemail greeting I made on Audacity into my phone. The only solution I found was to play the file on my mac or in my headset and put the phone in front of it but the qualify of the recording is garbage.
Any suggestion?
I was hoping you were going to say you have a Carl Kasell clip from Wait Wait…Don’t Tell Me 
But you are correct, it is an old problem without a solution:
https://discussions.apple.com/thread/252544503