SETTLED & CANCELLED CONTRACT BUT STILL ON STATEMENT

I requested a settlement amount on 17.10.2023 which was valid for 14days. I settled the contract and sent the cancellation document and id on 19.10.2023 (2days later). 1st November 2023 my debit order didnt go off, when i contacted them they said i have a credit, 01 dec 2023 it also didnt go off, but then the consultant said i can pay it into the account. i then noticed that the settled contract is still reflecting on the acc (with a credit) i queried this and they advised that the acc will be switched to pre-paid but i will still be liable for usage costs. i rep**** to say no i will not pay usage costs as this delay is not my fault, they had to update their records in oct already. Today i received another statement and this settled account is on the statement AGAIN. NOW I REALLY JUST WANT TO CANCEL ALL CONTRACTS WITH VODACOM. REALLY PATHETIC