All of a sudden I can't make a call w/my 5s. The screen keeps flashing between the regular phone screen to black. Tapping any of the other functions, yields nothing. It won't click over. If anyone has any clues I'd sure appreciate it. Right now I hav

Aall of a sudden I can't make a call w/my phone. The phone screen keeps flashing to black. It will not connect to any of the other functions I try to tap. If I try to call a contact, the call goes through. I can hear the person or voice mail on the other end. But that's all it will do, connect to a contact I select. However, they can't hear me nor can I turn on the speaker, select an option, etc. thanks much to anyone who might have a clue.