Tmobile canceling a line rediculous policy

i recently decided to switch from tmobile to another carrier. so i decided to switch providers and when i did i called tmobile. they informed me of their rediculous policy not only do you owe the previous months bill but they do not cancel the line right away so you get stuck payin for the month you didnt even use because they require 30 days prior notice so i ended up owing them 120 for the last month, 120 for the month i didnt even use any of thier service plus the 250 cancelation fee of 200 so all in all they got me for 500. this just struck me as rediculous and completely a rip off. i jus figured i would vent and inform people incase they did not know lol