FNB paid up letter

I straggle to get a paid up letter from FNB. Went to the branch in Kroonstad. Employee ther gave us tellefone nr to phone. FNB employee promise that will have the letter in 10 working day. It is 10 working days but still nothing from FNB. We went to ABSA. CAPITEC and NEDBANK al of them gave us paid up letters in a hours tine. Is is just FNB that's not willing to gave a paid up letter for something we paid up more than a year ago.