Unfair and ********* business practice

My contract was due to expire on the 30 of November 2020 and I contacted the MTN call center and got transferred to retention department to confirm termination/ cancellation. MTN now refuses to terminate this contract, they continue to bill me and have subsequently suspended my other lines due to non-payment of the bill of this contract that's supposed to be terminated. I'm being forced to pay for services I no longer need, and deprived of services I've paid for. The amount im being billed is R11 less than the amount I paid for 24 months, and im told the R11 is the cost of the device! Meaning over 24 months I've been paying R11 towards the cost of the device, which totals R264 for a Samsung J6 handset-how ridiculous because the retail value of that device is not R264! Now mysteriously they can't see the name of the consultant I spoke to in November because they did not make a note entry on the system, even though they can see that I did call because the call was transferred. If this is not resolved immediately ill escalate this complaint to the ombudsman and ICASA. To bind a customer to an expired contract is not only ********, but its ********* and ************.