OK brought this surround from a guy on Craig's list.Seems to be in perfect condition . I put my Sim in when I first checked out the phone and it worked perfectly but the battery fell out while it was on and now I can get a carrier signal (at&t). It accepts the Sim card because when you go into settings you can see my number populated and my voicemail number also but the phone says no network. Called 911 just to make sure the antenna is good and it is (yeah took a risk I know) tried the scotch tape on the back of the sim just to say I tried no good either took it to a friend who ran some diagnostics on it (whatever that means) he said it was good. Even checked to make sure the imei was unbooked which it is. What don't I know and what haven't I tried? I'm lost!