Billing

I am a customer of mtn for years. I have been treated very unfair this past months by this network. I opende a contract for steppe tablet for my son and the consultant that helped me didnt tell me that it was not a top up account becuase that is what i asked for and she put a limit on the tablet i never knew how it works to me nothing was explained , i got a bill of 2300 which i was upset for after phoning 808 and complaining several times nobody listened to my complained and they said i have to pay a bill i didnt even know abt.I eventually payed the amount on 17 Oct 2015 and they said there was never a limit on the tab then they put a limt on which i have proof of in a sms . Then i took out the sim and i didnt want to use the 500 Mb data from mtn i used a prepaid sim even swittched the tab off because i was still angry abt that huge amount this month november they billed me again the same amount but i never used their data nor the tablet its unfair and shady i want my funds back becauae im being penalised for mtn's lack of expeirenced consultants and bad customer service i only payed my own top up account and the 89 rand for the tablet that bill must be reversed its rediculous