I have an iPhone 5S on AT&T. This morning my fiancé tried to call and text me and the call was going straight to voicemail, and no text was coming through. I had no idea until she called my land line. I looked at the phone and it showed full signal. I tried to send a text and it failed to go through. I restarted the phone and the texts came through and everything was working normally. Something similar happened recently where my fiancé and I went to an area with no signal. When we went to an area with signal, her phone went back to normal showing signal bars, but mine was on "no service" until i rebooted the iPhone. My 5S is on 7.0.4. It was set up as "new". I have had the phone since thanksgiving and haven't had any problems. Also in the diagnostics and logs, there is only 1 log about an app crashing. Any idea what's the problem?