Mtn pathetic service

I had a contract with mtn and when i wanted to cancel i first went to the branch, i was told i need to either call or email their customer service center...i sent the email and it took them a week fir them to respond, just after they had responded i was sent an invoice , i disputed that invoice and i spoke to Zamuxolo Buyana whom after speaking to him i had no other contact with mtn.it was such a shock to me to find out that mtn has sent me to credit bearu , i called their customer service again i first spoke to William mentjies whom he asked me to pay the money and i did, sent him proof of payment and he did nothing with it. I called again and spoke to Anna shimbo who also did nothing about the proof of payment....my most concern with mtn how did they go about listing my name with the credit bearu without any communication with me, when i asked one of the consultants he told me that they did to my contract number , funny part about this response when i was terminating my contract i had stated to them that i no longer use that number and i did give them the number where they can reach me...i want my name to be cleared and i want my money back