I'm currently a Verizon customer and didn't have a SIM at all. ATT was worthless and sent me right to Apple. They were so crowded and backed up my only choice was really to leave it there which I did since it's useless anyway. I still have my Verizon phone activated. They are supposed to call me in a few days.....So far I am not please with customer service from either. Best I can say is at least the reps on the phone from ATT were nice. The inside ATT rep was just not helpful at all. I asked him if he knew the Apple store number and he told me "you have an iphone, look it up......) good thing my data was working then.....