Bad services from MTN

Had airtime contract with MTN but after my phone was ******, I called MTN to block the phone but they said they cannot block since it shows that the sim was removed from the phone. ok, so they told me that there was nothing they could do for me. I did not want to continue with the number, so I told them to cancel the contract and to my surprise it wasn't cancelled. I realized that MTN were now debiting R 1000.00 from my account. so when I investigated, realized that an upgrade was done on the same contract without my consent and the shameless MTN does not want to admit that they have ******* and ********** within their corridors. From March a ***** case was opened and I have done follow ups but have been taken from pillar to post. Now they have handed over my account to their collection department.