Poor service

I have been a customer of FNB for over 20 years. When I was doing better financially, they convinced me to move to a Platinum Acc to benefit from additional perks and services. In recent years, things haven't been great and so I made a request in Aug 2022 to downgrade my account to a Gold Acc, which they did in part, in that it reflects that change on my statements and internet banking. They have however continued to charge me the full Platinum Acc fees ever since. I have made several complaints, even going into my branch to try to resolve the matter, yet they cannot seem to resolve this simple request. My branch simply defers blame to another department and so it never gets resolved. I am seriously ****ed and concerned they are unable to assist me with more serious matters...