I've had it sine the first day it came out. It worked perfect till over 24hrs ago now. When to get on the net on 3G and nothing and had full bars. So I flipped airplane mode on and off and still nothing. I've reset network settings done a hard reset and have restored in iTunes to new phone. I've talked to AT&T they said nothing is wrong with the network. I talked with Apple twice now. Whent through all the steps and still nothing. The crazy part is the gfs 4s is the same way? Apple said they would send a replacement. But could not promise a new one. I've only had it 3 weeks. I'm going to AT&T store in the morning to get a new sim to see if that helps. If not I'm going to Apple store to make sure I get a new one. One crazy thing is wifi works just fine?