The back piece has also become a bit loose at the bottom left corner (the same side as the sim card), I've called Apple and they say it will cost me $170 to fix that part as my warranty expired 11 days ago (always how it works eh?). Any ideas on how to fix either of these problems would be a great help!
Best answer by Mo D.
Is this a new SIM card or did the problem just start recently and it was working before? If it just started up, sounds like you've got a faulty connection going due to the coming loose of the parts. Lots of 3rd party stores offer fixing, and since your warranty is out anyway, might be worth shopping around. If this is a new SIM, then it might just be the SIM that's a dud. It happens sometimes.