No Service on a complaint or query

I opened an account last year after receiving an SMS and at the time was looking to change banks. It started off well but is now horrible. I kept calling for information on the SMS in received but the moment you call the person on the other other end either ends the call while you are on the line or pass you through to someone else or tell you they have IT issues. There is never really any help. Asking to speak to a manager is never granted and the agents are terrible at giving information. They did not give all information, they are lazy and while all of this I am not assisted. I have raised 1 complaint over and over again. After weeks of no feedback I get an email that states I am wrong and that's that. I reply saying they need to relook this claim only to have no feedback after asking for a manager to contact me. I am not always able to answer my calls but email communication would suffice too. The end result should be the client should be assisted to the best of the company's ability, yet nothing. I want to close my account with FNB because besides this they also had my app stop working meaning I am unable to do anything on it. I am not able to go to the bank. The app and calls to FNB should be my saving grace but this is another nightmare. The branch I visited in December also gave me ****ty service.