FNB fix

I have 4 "declined foreign t 457" transactions that cost me R8.50 each in the past month. I don't understand why FNB is allowing that to happen on my account without letting me know what it is for!. It is deducting money from my account without any permission! Everytime when there is money in my account it deducts -R8.50 per day, it is costing me to lose money for something i have no idea about.