Unauthorized debit order

I don't understand how MiWay decides to run a debit order on my account before the date of the actual debit order I had chosen on my side. Now I have incurred charges for a bounced debit order and besides the money, now my account shows that there was bounces debit order, which looks bad on my credit profile. I really don't know who authorized this debit order which has ****** inconvenienced my big time!!!!