iPhone not ringing or showing incoming call
My iPhone frequently stops ringing and showing that I have an incoming call. I have checked the volume..it is turned all the way up. I have checked the side switch and no orange is showing and the bell has no slash through it. What I do get is a notification of a missed call. When I do a hard reset it seems to fix the issue for a while, then it will go back to not ringing. I also have an issue with the phone turning itself off. I won't know it's off until I go to use it and have to do a hard reset to get it back on. Any suggestions?
iPhone 4S, iOS 5.1.1