Ok. So I have a myTouch 4g. I switched numbers. I go into my "about phone" section and it still shows my old number. I'm using the same SIM card. How do I get the phone to show my new number?
Call tmobile. Something got screwed up when they switched it for you. Are you having issues with getting text messages and phone calls from your new number?
I agree with iamlilysdad... talk to T-Mobile... but testing it by sending or calling a friend to find out what phone number is on your card... the phone number is not stored on your device, it reads it off your card when it boots up.