FOREX ERROR TRANSACTION - *****ING

I have made a Forex tranaction in May, suddenly they keep on deducting "Forex fee" which was already paid for when the payment was made. And they are deducting every month more and more. I made also a Forex payment in March and I paid R200 for a transaction of just under R10,000. And now, I am paying R720 and counting for a transaction of just over R5,000. This is NOT acceptable! This is *****ing!! I am not taking the excuse of 'Forex transaction' and this is still going on!! And I paid for that transaction already when it was done! My account needs to be rectified!!