Home Internet Gaming Problem

I used the t mobile home internet and it kind of sucks, i used it only for 3 days in month of August and i was charged twice on that part, i am too much tired of this billing issue, T home internet simply did not worked for me. I cancelled it on 3rd day but still got charged for the bill in sept also. this is too much .. They ask for pin everytime which they never set up me up for. simply their service is worst..