Recently, I purchased a new unlocked GSM cell phone for my wife to use on the AT&T/Cingular wireless network. After inserting her SIM card, the phone recognized the Cingular network, and displayed five bars. As long-time Cingular customers, we expected the phone to recognize the network and make and receive calls. Unfortunately, it was unable to send nor receive phone calls. It was, however, able to send and receive text messages. Thinking that AT&T needed to enter the phone's IMEI number, I brought the phone to the local AT&T Wireless store. They looked at the phone and verified there was no problem with the account, and suggested that I call their technical support to resolve the problem, after mentioning that they had received many calls about unlocked phones being able to send and receive text messages but unable to send/receive phone calls, due to a recent network change.
After I spent quite a bit of time on the phone with AT&T customer service and technical support, provided IMEI number, swapped SIMs and power cycled several times, they made some changes on their end, all to no effect. When I mentioned the network changes cited by the local AT&T store employee, the customer service rep stated that he had no knowledge of any such change, and stated that tests they conducted on their side indicated that I had a defective phone.
Today, on a hunch, I put my wife's SIM card in an old unlocked Blackberry that had worked the last time I tried it a couple of months ago. Guess what? Same symptoms as the new "defective" phone -- it would not make nor receive phone calls!
Is anyone aware of a change to the AT&T wireless network to disable unlocked phones? As hard as it is to build customer goodwill and easy as it is to destroy it, one would think that they would not intentionally do this to their paying customers. As always, comments are welcome.