MTN submitted my account at Shapiro shaik defries with R8739.55 now i paid almost R14633.33

I took a contract from MTN 2014 and they didnt debit my account for 3 months while i kept going to MTN enquiring why am not debitted until my account submitted at Shapiro for Debt collection

My account was submitted with R8739.55 while my contract was R189 a month for 24 months which it was about R4536. So when MTN submitted my account they doubled the amount i paid my account from 2015 june till today am still paying which its almost R14633.33 and am R1337.75 outstanding

I email Benny a team leader at Shapiro which he failed to explain whats going on with my account because if i add outstanding amount it goes to R16k which is double of R8k that was submitted to them by MTN

Where can i log a complian as this a day light *******

Please advise