Bad service .

i would like to complain about my debit order amount last month mtn took R986 i didnt complain i went to the bank and reversed my money and went instore to pay them inturn they closed my account still didnt complain went i nstore to inquire about my account and was told that it was migrated to something and the lady who helped me apologised and opened my account, this morning i wake up and mtn has done it again they have taken R1144 from my account for a contract of R299 a month someone please help me as i cannot be going to the bank to reverse this money who is going to pay for my bank charges and i feel iam fed up with this now i dont want this contract anymore my lord if this is what mtn is going to be doing to me every month