I unlocked a 3GS and sold it last week. I unlocked it through AT&T as I had done with a few other iPhones and that went well. Sold the iPhone and the person I sold it to said their SIM Card is not being accepted but the phone (yes it is the right size and it is on a GSM network). It keeps saying no SIM Card detected. Now all the other iPhones I had sold were almost instantly unlocked. This one keeps having issues. I instructed the buyer how to put the phone into DFU mode and do a full restore and it still isn't working. Now AT&T says it can take up to 7 days. Has anyone actually had it take that long?