Refusal to correct subscription

Hi<br> I renewed a contract with mtn in November 2014. It was a contract which gave 200 talk time minutes and 300 mb data the contract cost was R229 pm. I also received a mail from the agent at Fourways mall confirming the rate of R229 pm<br> The following two months I noticed they were debiting my account with R289 pm. I then went to the shop to discuss this inconsistency with them and they informed me this particular agent Hardship Mavenga would contact me which he never did I went there a second time and he was not in<br> I then sent emails tho mtn customer care to sort out the problem<br> There response was that they calculate the fee to be R289 pm I again stared that I contracted for a R229 they then stated they did not have a copy of the contract. I sent them a copy of the first page I received from the agent<br> I have requested them these numerous times to refund me the R60 pm they have been charging me and to correct my debit order to R229 pm but to no avail<br> I have even tried phoning them but the line remains unanswered and eventually cut off<br> Could you please follow this up<br> Thanks<br> JH Liebenberg