Old thread I know but I was having this same issue, make a call, fast busy signal and even after hanging up, the busy signal wouldn't stop. Had to restart the phone to get it to stop. Couldn't make or receive calls. . I'm on Sprint, evolte, but I have good news! There is a real fix. Called Sprint, tech support had me change my MSID number, fixed! Had me go into an editing mode and they assigned a new MSID number and I'm all good. I'm hoping that this can help someone else out there going through the same thing.
Sent from my EVO using AC Forums mobile app