The Washington State Attorney General, found that T-Mobile's new no-contract plan was in fact a contract and there was deceptive advertising that lead consumers to believe that there no annual contracts or hidden charges when in fact there is an Early Termination Fee (ETF) and balloon payment if yo want to get out your T-Mobile plan when you buy a phone.
So if you bought an HTC One and don't like it or realized that although the iPhone 5 is better deal than other carriers, you can get out paying for the phone and the T-Mobile Mobile contract if follow the guidelines by the Attorney General that follow.