incompetence of MTN as a service provider

I had two contracts with MTN, a cellphone and a tablet. In May 2015 I was told to cancel contracts on the 6 and 13th respectively ask didn't want to upgrade. I did as asked, spoke to a consultant who assured me that my last payment would be the 15 May as that is my debit date. I have the names of the consultants and reference numbers for both calls. In June 2015, MTN debited my account for both contracts. I went to the store at Midlands Mall and spoke to Ricardo. He assured me that the contracts will be terminated immediately and no more money will be deducted and MTN will reimburse me the money they took from my account. As we were discussing this, he realized that MTN stopped the incorrect tablet number and that MTN was billing me incorrectly. Naturally he assured me all will be sorted. I go into the store at least twice a week to try and resolve the matter, now, I am not going to be understanding or patient as once again for July 2015 MTN has debited my account. It really should not take 2 months to cancel a contract and MTN should definitely not be taking moneyfrom me!! For such a large service provider their customer service is beyond pathetic!!! I will NEVER support MTN!!