Personal loan Settlement later

I have a personal loan with FNB and i paid it off now i need a letter of proof that the account is paid off they telling me they cant send me because there is money they have to pay me back before the account is settled and closed. Am really not happy with the service they giving me because i need this letter to prove that this loan is payed off and i need to prove it immediately. this letter wont be of use to me next week or next month. I even asked one of their call center agents to send me an email that says the loan is payed off but she said she is not allowed to.