Mtn do not want to cancel my expired contract

I had a call and data line with Mtn, that were transferred from Altech Autopage when Altech closed shop. Towards the end of last year my contracts we coming to an end and I had to cancel. For a few days trying to call Mtn retentions to cancell with no answer. Went into their service center and was told the only way to cancell is via the call center. I resorted to email. In the meantime they called me several times to get me to upgrade, and I woud try and use that oppprtunity to cancel instead, but was told to call a differeny line. I did , with no luck. Contract expired and still my emails to cancel were not being entertained. I then canceled/stopped the debit orders with my bank. A few weeks later then only they called to try and ask me again to upgrade, I couldnt, only then was my call line cancelled. The data line was not. Every time I would receive an account statement I would reply and ask them to cancell the contract. All of this happend between July to roughly November 2017. In March this year i was told I need to pay 911 odd rands to cancel my account. I questioned this. No one cared to reply or explain the amount. My case was handed over to debt collection. Finally some one called, and some one listened. They asked me for proof of emails sent to Mtn to request cancellation. I did and they forward those to Mtn and asked them why was my account handed over. The same reply came and said the client need to pay that R911. I recently decided to pay to put this matter behind me. Now, they have sent another email saying that amount is not enough as my last payment was September 2017. Like! This was now Emma Mathanjana from their legal. Previously, Kamohelo Mosia, Robert Bongani, Matlakala Tefu, all from legal, participated in this mess. The names and number of customer consultants who rep**** are just too many to type in. Can i get someone competent to look into my case and assist me, please.