Mtn steeling money with lame excuses

MTN has been taking too much money from me every month for my contract and now they want to blame it on the fact that I came from autopage which was out of my control and I didn't have a option. It took forever to get an answer on why the money was being taken, I had to call and drive to a branch 3 times. Only when I complained here did I get an answer which was not good enough. I left autopage very long ago, longer than a contracts term so I don't understand how I need to pay more monthly now!! I want my money back that I was billed ekstra for since Oct last year. I did not give concent nor was I informed that I will need to pay this!!