Fnb home loan. Not closing settled accounts.

Hi my loan was settled on the 18 Dec 2018, but I am still getting statements from FNB, saying I owe them. During Jan 2019 they refunded me the overpaid amount, but the account is still not closed. I called them and they reversed the charges as bad debts not recovered, but the account is still active, I called them yesterday and told them to close the account I checked today the account is still active. I have an audio recording of my last conversation with them yesterday.