No help for paid up letter

Good afternoon. My husband had a loan with fnb. Last week he paid it in full requested a paid up letter. Today he was on the phone with them for this letter, going from one consultant to another and it ended up with no awnsers. He paid every month now that he is done paying he can't get the letter from you. This is unacceptable as for there is no issue when you asked him to pay now he is just asking for a paid up letter and no one can help him