No response from FNB

I settled my revolving loan, overdraft and credit card two weeks ago and have emailed proof of payment to the relevant departments. I requested paid up letter but have not received a response to date. I contacted FNB this morning and stayed on the line for 20 minutes. When my call was not answered, I spoke to an agent over the secure chat feature on the banking app and she phoned me and routed my call to the relevant department. I waited on the line for 36 minutes only for my call to be dropped in my ear. I urgently need this matter to be seen to as this is by far the worst service I have received from a bank, and I have literally had accounts at almost all major banks.