Thanks for posting in the community! Sorry to hear about the call audio issue, but would be glad to help!
Tony - Community Support
Has anyone found a solution to this issue? I tried the Settings-Accessibility-Bluetooth and it still didn't work with a phone call.
Thanks for reaching out to us!
Just to help isolate the issue, were you able to test the headphones on a separate mobile device by chance?
What is the current mobile device you are trying to use it with as well as the software?
Let us know so we can further assist!
That's a great question. Here is a page that talks about updating (it's about headphones but the procedure is the same)
Tony G - Community Support