So I've had my iphone for about a week and a half now, and it's my first one. Last night and this morning I've realized that I can't make or receive any calls or texts, it rings twice then goes to voice mail when a call comes in. When I try to place a call, it just says call failed, and same with the text messages. I've already restarted it but that didn't seem to do anything. Is there anything else I can do to fix this?