I picked up a replacement for my 3G (had cracks around camera and stuck pixels) at the Genius bar yesterday and by late last night, I had no service and the message "Restore iPhone - iPhone cannot make or receive calls..." was displayed. The phone was working fine when I received it and I even used it to make calls. I did noticed later on with my signal, where I typically have 2-3 bars, was down to 1 bar. Later on, it just went to No Service. I tried all the typical troubleshooting methods like restart the phone, pulled out the SIM and placed it back...nothing. So I tried a regular restore and then a recovery mode restore. Still no service. I put the SIM in my old razr, and it works fine. I made an appointment at the genius bar once again. I hope they can just perform some magic to get it working rather than replacing it. Anyone else experience a similar issue?