I bought my iphone back in late September and ever since I've been having this issue with the sim card where it occasionally and randomly reads No Sim Card. To fix it I have to restart the phone which isn't too bad but really irritating if I am playing a game or on the phone. I work in a cell phone store so I pretty much did all the trouble shooting I would do if someone else had the same problem. Bought a new sim card, updated the phone to latest iOS, updated carrier settings, backed up and reset phone, everything. Would apple replace the phone or would I have to leave it with them to get repaired? I use my phone frequently at work so I really don't have time to leave it there to get repaired so I'm hoping they can just replace it like they did with my iPhone 5 when the sleep/wake button was not functional. The phone is in excellent condition with no drops by the way.