mtn service is pathetic

Mtn decide to give me 4gb data on the 14 of sept normally i get 100mb, i ignored the message cos i thought its one of those promotional msgs. The next thing i get a statement saying i'm owing R891, immediately called the call center they tell me i self serviced my self with data, how i dnt knw because i cnt buy data wen i dnt have airtime, no one wants to deal with the matter. I'm thinking of opening a case against mtn, i'm so frustrated right now i cannot accept what mtn is doing to me they were suppose to ask me first if need extra data not to jst load it without consulting me, I also asked for settlement amount i'm still waiting it seems they dnt want to give it to me, jst want to end this contract i hv with mtn bcos u will never knw wat they will do next, wat a pathetic treatment i got frm mtn. I regret why i took a contract with mtn.