Credit Card Account Closure Letter

I have paid off my FNB Credit Card on the 12 January 2026 and it was confirmed that the outstanding balance has been settled and the account will be closed as i have requested the account to be closed. I also requested a closure letter. On the 14 when i enquired i was told that it is still owing. i needed to pay another amount of which i did and i was assured that the account will be closed and the request for closure letter will be logged. From the 14 January i have been waiting for the account closure letter. Whenever i enquire im told that the case has been escalated. I am frustrated with FNB and this is on the reasons why im leaving the Bank. The Bank claims that I have a Private Banker but this is non existent. For someone paying so much monthly for Private Banking Facility should not be experiencing this issues. Is it too much for one to ask for a proof that the account is closed?