Unfair customer treatment

I had a contact with mtn .It was supposed to be 24 months. However due to unforseen circumstance I had to cancel I asked for a settlement amount it was given to me .I was told to pay into an and a account .which I did .how ever i called in to make sure the account was canceled. And a consultant from mtn confirmed to me it was and I do not owe anything. I also was adviced they won't debit my account. Few weeks later my account was debited .And left in a minus on top of that they canceled my out going calls saying am owing R1380. I feel this is a fair treatment since I have been calling and I can't get any one to answer me.when I went to store I was given a number to dial.