MTN ******* billing and no response

I signed a new contract in March which took affect from 1 April 2015.<br> <br> A month later and every month since, even though I never exceed voice & data usage the debits have all exceeded the contract's monthly subscription.<br> <br> I managed to log 2 billing disputes on the 13th June (billing ***) and 15th July (billing ***) with a non-striking representative (Nolovuyo) at MTN Morningside branch who advised my rates were hiked for no reason.<br> <br> To date they have not bothered to correct my contract subscription to the amount signed for from April nor contact me.