Unhelpful agents and no Manager to speak to...pathetic

Called FNB Finance in November to change my payment date from the 3rd to the 28th of the month. The agent I spoke to confirmed the change , advised that I would not be debited on the 3rd December. Unfortunately, I was debited on the 3rd December. I was under the impression it would amend itself the following month. I called mid-December requesting for a statement, also checked if I would be debited the 28th December. The agent confirmed this. Once again, no debit on the 28th, I was debited on the 3rd January. Called again early January 2022, spoke to Roxanne Khan, advised her of my query and politely asked to speak to a Team leader/manager advising her "Nothing against you, however, I need to speak to a manager as no agent has managed to help me". Agent places me on hold, after a few minutes, ID's me, places me back on hold, after a few minutes asks me some more questions, places me on hold again, comes back and asks me for my query. Over 17 minutes speaking so someone and no manager. Her last statement was that they don't have supervisors where they are. Pathetic service.