MTN - Rewardsco

I had an upgrade with MTN cancelled by Rewardsco - ref ***3 in December 2018. However I am still being invoiced for the contract and when I try to convert the number to pre-paid, MTN refuse, saying the contract is not cancelled. Rewardsco insist it is cancelled, I must go MTN. MTN in La Lucia Mall laugh in my face (Sandra Noxolo) calls Rewardsco (on my phone) and shouts at them that they are ***** to send me to them. Kailash also from La Lucia has tried to help and failed. Everyone advises me not to instruct my bank to stop the debit or I will be "blacklisted". It appears a mafia business.