I've been having issues with people eharing me on the other end of calls with my Iphone4 today. I can recieve calls, and make them, buty the other person can not hear me. Mute is not on. I've reset the network settings 4 times. I've hard booted twice. When I hard boot (top button and home button together) I seem to have the ability for people to hear me for anywhere from 15 minutes to an hour, until it happens again in the middle of a call. Any suggestions?