FNB Personal Loan Is total shambles!!!

FNB customer service is shambles, for the longest time i could not pay my personal loan due to financial constraints.I had made an arrangement to pay it off monthly and luckily in August I had enough money to settle in full, now that I have paid they cannot issue an interim paid-up letter. I have been calling since last week Tuesday(25 August 2020) with promises that I will receive it in the next 48 hours but till this very day nothing has come through to my mailbox