Paid up letter not supp**** by FNB

This is the 2nd time I settle a credit account with FNB and they fail to supply me with a paid up letter. I have settled a credit card legal with FNB of an amount of R544.57 on the 2018/07/09 this is a payment reference number of ********** 401926. After payment I send them the proof of payment and ask them to close the account. They told me after 3 working days I'll get the paid up letter. I called on the 13th July 2018 but still I haven't received the paid up letter. FNB has a tendency of not supplying with paid up letters in time when payment are being settled because with me is not the first.