FNB Foreign T

I’ve had my account for about a year, and I keep getting charged R8.00 randomly. It has reached a point where I frequently go into the negative balance; whenever I receive money, a portion of it is deducted. In just one day, I was charged four times by foreign T 457~ (the number is longer but I’m not comfortable with sharing it). I would like to understand why I am being charged and if there is a way to prevent these deductions.