Bad customer service with FNB loans

I have a personal loan with Fnb and they have double debited me for my account, I have been trying to get 1 payment reversed from the 1st of July and still haven't received the amount, I have made 4 calls to them and they keep on advising me that they have sent an urgent refund through on the 1st call which was made however its already 22 days in the month and I still haven't received the funds everytime I call in the agent tells me the same thing and advises me they can't nt get me to speak to a Manger and will get a manager to call me back it's been a week and I still haven't received a call from the manager and still haven't received my refund. FNB should really work on they call center agents customer service which is terrible and how they handle the customers, they are very fast to call you when you miss a payment on your account but will not be able to assist when they have to pay you money that belongs to you, I have been banking with them for more then 5 years and am very disappointed with the service that I have been receiving.I have been on the call each time. For over an hour and still nothing has been done about it, I hope they do read the bad reviews they get and actually take action against this