new year, new problem DECLINED FOREIGN T457

I've had several "declined foreign t 457" transactions that cost me R8.50 each in the past 2 days I don't understand why this is happening to my account without letting me know what it is for!. It is deducting money from my account without any permission! I started facing this problem this week and i'm trying tounderstand why FNB is letting this happen to my account. I would like an answer please because this is seriously stressing.