unauthorized debit order

I AM AFFECTED BY THIS UNAUTHORIZED DEBITS ON MY FNB ACCOUNT, • FNB :-) R99.99 paid from cheq a/c... Ref.Gr Life Gr Lifes 7 • FNB :-) R129.00 paid from cheq a/c... ***.

WHY BANK FAIL TO PREVENT THIS UNAUTHORIZED COMPANIES FROM *****ING FROM US?????????????? I STOPPED AND REVERSED THIS TRANSACTIONS BUT CAME WITH A FEE FROM THE BANK.