Foreign T 412752*199 6 -R8.50 Unauthorized charge

Declined Foreign T 412752*199 6 -R8.50 An unauthorized debit order. has put my account on a negative balance and I don't know where these charges come from and FNB has not resolved this issue cause it's still happening. I'm starting to think that I made a big mistake by banking with them, I am really disappointed in this. I don't want to close my account but it looks like I don't have a choice.