VERY DISSAPOINTED IN FNB

I have been banking with FNB for a very long time and for the first time i am really disappointed as R600 was debited from my account which was not authorised by me so to me that is basically *****ing money from my account..I have not been contacted to make payment arrangements for the short term loan i took out a couple of years ago so how can they just take money? I have been unemployed for a while and have only recently started getting onto my feet and the money that was deducted belongs to a client for an item i need to make for them . When trying to contact FNB i just get transferred from one department to the next or the number doesn't exist or get answered which is very frustrating or i get told i need to dispute the amount . It i looks like i am not the only one that this has happened to if i look at the other complaints on HELLO PETER . I am sure alot of clients are going to close their accounts if FNB carries on like this