Hey, new to the forum, neat place!

I bought a T-Mobile Samsung SGH-R225m on eBay as a back up phone. The phone was locked so I had a friend call T-Mobile (I have Cingular) and provide the IMEI # so they would send the instructions. They sent the instructions and the phone unlocked perfectly.

I dropped my Cingular SIM card in and it started up and registered to "AT&T Wireless". I can make calls fine from the phone and even SMS. I problem is, the phone won't accept incoming calls. When I attempt to call the phone I get one ring, a long pause then "doot-doot-doot" three times and the call is ended.

I'm starting to get pretty frustrated with this as unlocking it was hassle enough! Could anyone provide a solution or shed some light on this issue? Everything is working fine from my Cingular phone of course, Samsung x427m. Calls can be made and recieved from it.