MTN DID NOT CLOSE ACCOUNT AND NOW WANT ME TO PAY ANOTHER LUMPSUM TO CLOSE IT

I sent an email trying to request the closure of my contract account that had since turned into a monthly prepaid type of account. I was told they would deduct a lump sum and then I should send an email when it's deducted and only then would the account be closed. The amount was deducted, and an email was sent on 16 November 2021, for two months after that, nothing was deducted, and I thought the account was successfully closed. Only to find out that I have been sent over to lawyers and the account is in arrears. I cannot physically go to a branch since I am currently out of the country, but I cannot stress how inconvenient and frustrating MTN is right now. I have written to their retentions department, their Twitter and Facebook accounts, and called explaining that this amount was deducted. MTN should have closed the account as they had explained to me. It's not fair that I must pay an arrears amount on an account I thought was closed.