Unauthorized debit order for ended contract

I am very disappointed by MTN South Africa 2020 I signed a contract of 24months for Wi-Fi router, I’ve never missed any payment up until my contract came to an end in August. In July I’ve been getting calls non stop from their call centre I made it clear that I don’t want to extend it I have Unlimited Wi-Fi at home. I called their call centre again just to make sure they cancelled the contract & they confirmed cancellation, it came as a shock to me when they sent me a bank statement via email to say that I need to pay R511 mind you I was paying R250 for my contract, How is that possible?

I never used the data they are giving me every month after I cancelled the contract but guess what they are still deducting it every month. I went to MTN South Africa (In-Store) & MTN in Canal Walk they said they can’t help me I need to call their call centre which is the call centre sent me up & down they send your call to someone & the phone rings alone. I even sent them an email & that was useless.

I would never advice anyone to sign a contract with MTN their service is very horrible. They are telling me that I need to pay the outstanding amount in order for them to cancel the contract other than that they gonna keep on giving me the data that I don’t use & they charge me five hundred bucks that’s insane.😡😠