Nobody is forcing anyone to use T-Mobile. There's no contract.
Hey, Sprint. You owe me $2000 for that two year contract where you sold me a defective Galaxy S2, put me on a "4G" WiMax band that didn't work, and then said there was nothing you could do about the phone crashing or the 4G being somewhere between zero and 16 Kbps. I'll start believing you when the check arrives in the mail.