Exploitation from MTN south Africa

I took MTN SIM only contract which was month to month which means no commitment to the contract. It's only a month contract. Then another month I couldn't pay and my account was suspended but to my suprise the account have allocated monthly installments. Now I must pay for over R2000 for the service I didn't get as they already suspended my service (account). Contract was R230 a month and now I have to pay the amount times 8 while I didn't use their services or benefits of the account. I need MTN to solve this problem because they even listed me on credit bureau.