UNAUTHORIZED DEBIT ORDER

MY ACCOUNT WAS DEBITED WITH R350 ON THE 27/03/2015 BY HDL TRADING. WHO THE HELL ARE THESE PEOPLE AND WHERE DIDTHEY GET MY ACCOUNT DETAILS !!!<br> <br> WHO GAVE THEM THE RIGHT TO DEDUCT MY ACCOUNT .<br> <br> I HAVE CALLED THE BANK TO REVERSE IT BECAUSE IT IS UNAUTHORIZED.