FNB taking money from my account

This is now the second time FNB took money from my account without my authorization. I have been paying the debt collectors and for the past two months when I pay them I rejects. I called them and only recently found out my account is with a different collecto. They called me but the lady was so rude and had no customer experience what so ever. I called FNB because I want tyou pay the account and would rather let them have a direct debit order but they refuse to assist. Clearly they don't want me to pay them but want to take money from my account if and when they want too! I want my money back in my account! This is the second time FNB does this and I have been a customer of there's for more then 12 years but I'm being treated like a new customer. As a loyal customer to FNB I at least expect some communication from them because this is not a few hundred it is R5940.00.