Paid up letter

I have been requesting for a paid up letter from FNB for 5 days and they cant help me with it, I don’t understand what’s so difficult by drafting a paid up letter for an account thats already closed, FNB is always on your neck to offer you their pro****s of which you subscribe to, but when you need them they take their sweet time. I need this paid up letter so urgently but to them cleary they are unbothered.worst customer service