Unknown Debit order (*****)

My account was debited with an amount of R2300 which I don't know of. I called the bank to reverse the money because I don't know who debited my account. They told me they don't know who debited my account and I must call that company directly since they cannot reverse the money. How is it possible that ********** activities happen in my account and the bank says they don't know? I really don't trust FNB anymore and I hope this is attended to by someone more competent Noluthando Ncwane -*** / ***