Tmobile presently is refarming their network. I have the same issue ,my phone failed to received calls and text while I am in New York city where I work. But no single issue in New Jersery where I live. My data is lightning speed in New Jersey but 3g or Edge in New York. Try to contact t-mobile , they might have issue on the tower near your place. Try to change the sim card. For GS2 ,unable to hear the call, or with echo. Do a soft reset>turn off the phone> pull out the battery for a minute>put it back then turn it on.