You might also need a non-gba micro sim for EDGE to work on tmobile. Wasted a lot of time looking for it as they are discontinued. You might get lucky and find one still sitting at a tmobile store. The card holding the micro sim would be blank instead of a photo that tmobile usually prints on the card. And also look for the 50.01 printed on the edge of the micro sim itself. Had a relative with this problem so we just cut his old sim since he hadnt switched to a gba SIM yet.