Unauthorized debit order and rude and unhelpful customer and retentions staff.

I had 2 contracts with MTN which expired in 2022, I called and requested a cancellation, 1 number was terminated and another was kept on prepaid as I alluded to the agent that I was looking for a router which they did not have at the time. A year later, MTN is trying to debit my account for what reason I do not know. I called 083135 and I was transferred from pillar to post by extremely rude agents from customer service and retentions. I will not pay that amount and I will also contact the ombudsman and you can explain to them as to what service have you provided me that warrants for a debit order on my account. Number in question: *** (which by the way is marked as invalid when dialed on the option selections) contract: BA***.