UNAUTHORISED DEBIT ORDERS

I HAD AN UNAUTHORISED DEBIT ORDER ON MY ACCOUNT FOR R89.99. I AM NOT WILLING TO THE BRANCH TO HAVE IT REVERSED AS I HAVE NO IDEA WHY AS MY BANK YOU WOULD ALLOW UNATHORISED DEBIT ORDERS. AND GOING THROUGH HELLOPETER I SEE THAT THIS IS THE NORM AS I AM NOT THE ONLY CLIENT WITH THIS ISSUE. THIS IS THE REFERENCE - KUKHULE /KI280219S2154. I NEVER SHARED MY ACCOUNT WITH THIS COMPANY NEITHER DO I KNOW WHO THEY ARE!!!