Standard Bank refusing to give me settlement letter for a closed account

I had a home loan account with standard bank and the house was sold in July 2019. I have called the bank several times to request a letter stating that the account is now closed as per my conversations with several of the bank's employees (spoke to Ronwyn and Zanele most recently) and every time I'm told the account is indeed closed, but none of the consultants are able to send me the letter stating as such.

I eventually got hold of someone who told me my account is closed, but someone named Tayyaba Deonarain would contact me. I reached out to Tayyaba to find out what the problem is and no one has gotten back to me. I even found the group email for the bank's internal complaint resolution centre and sent a mail to them before I came to HelloPeter in frustration. No one has gotten back to me. Their complaints resolution line (***) just kept me on hold for almost 20 minutes on several occasions so that does not work either so all their channels are essentially useless to consumers

This is kind of service from such a large organisation such as Standard Bank is completely unacceptable