Does your T-Mobile coverage go on vacation as soon as you cross the threshold of your own house? If your phone is dropping calls as soon as plop down on your couch, call T-Mobile from today on and threaten to leave.
The company may send you a signal booster to get you to stay. It's described as "a new device that boosts T-Mobile's 4G/3G signal throughout a home when installed," but does require at least one bar of 3G anywhere in the house to work.
Be sure to return it if you do cancel service, or you'll be responsible for $500 in fees.