T-Mobile Secret Codes

Samsung Galaxy Nexus I9250 (Google) Hard Reset Done

To get through to customer services, dial 150, then press send. As soon as the call is active, press options, then select send dtmf. Now type in 150, then press ok. you should hear 3 beebs, and a second or two later, you’ll get put through for free.
Ever deleted your voice mail number? If on T-Mob, dial *#67# send, it will show your voice mail number.
Press #225# then send to check your credit balance . Press *#646# then send to check minutes used.
#646# will show a T-mobile user how many minutes used and remaining also the date of bill close. #674# does the same thing for texts.
On Hungarian T-Mobile you can see your own number by typing *121#
On any T-Mobile phone you can dial +16111 and then the number you are calling to call out 4 free. It’s great when Ur out of time on prepaid. You’ll hear a female voice saying something like Ur call can’t be completed. Hang up and immediately call back. (not tested, report if it’s not working.)
On T-mobile to get your account balance call #999#