Fnb should call it quits really service is beyond pathetic

I called in yesterday with an issue that was escalated last week Friday already. Today is Tuesday and no one has called me back or even bothered to follow up. I wanted to speak to the head of online/ digital banking and I was told they are not allowed to receive calls and the manager will call me back by close of business. it is the next day already. I don't see the sense in this platform if no one gets back to you. Where can one raise your concern about unsatisfactory customer service.