MTN incompetency

I cancelled my contract with MTN December 2020. I received my cancellation reference number : *** from Nontobeko Mkhize via e-mail. Low and behold, MTN deducts money off my account again. I sent an e-mail to Nontobeko Mkhize to contact me, but no response. I called 083 135, had to listen to the 2 minute UNISA message and got through to Zanele in the pre-paid department. According to her my cellphone number shows up as pre paid and not contract. Since she could not help me, I asked to speak to a manager. Well, it seems the rats left the ship, because no managers on duty. I was the transferred to the contracts department. A person identifying himself as Deon tell me the system is down and I must phone back in 2 hours time, It amazes me that MTN is still in business or it simply because the fools like myself are stuck with no way out, paying for a contract that was cancelled, and simply *********** salary collectors!!!