Default [Q] Can't hear callers, they can't hear me

T-Mobile S4.

It started out of no where. When I get calls, the caller can't hear me, and I can't hear them. The weird part is that after a clean flash it will usually work for a little while. But after a few hours, the issue returns.

At first I thought it was a Cyanogenmod issue, but the issue also happens in TouchWiz.

Wi-Fi Calling works fine. Data works fine (i can surf the net, etc...). It's just calls.

There was a period for about a day where when someone would call me and I would answer it would make this loud tone to the person who was calling. That doesn't happen anymore though.

Please any help would be amazing.