Failure to reversed unauthorised mweb debit order.

I am annoyed that when I stopped a ********** / unauthorised debit order, it was stopped and not reversed. I had to go to the branch again to reverse. After my first time at the branch another debit order went through which was reversed for insufficient funds. Now I get sms that it is affecting my credit rating. Surely if a debit order is not authorised it should be reversed the first time. A method also needs to be put in place to always stop these type of debit orders trying again, it is silly to wait for it to debit again and then reverse, it should be stopped at the attempt.