Paid up letter

I made an arrangement to settle my FNB by debit order on the 29 May 2020 on the 7th of May 2020 and I was promised that a settlement letter will be send to me before the debit order goes off, but to my surprise no letter was send to me, on the 29th May 2020 I called the call centre and I was advised that I should move the debit order to the next day the 30th May 2020 and I will receive the settlement letter within an hour. The debit order went of on the 30th May 2020 and Up to this day I have been in contact with the call centre agents one of them being Ashley and I have not received anything. I have send numerous emails with no feedback. I cannot close my account without the letter. Send the letter as promised