Unauthorized debit order

I noticed a debit order on my bank account and found a contact number *** for the company that executed the debit.<br> Called them and was informed that they are a collection agency and did the collection on behalf of MA Marketing. I was given the contact number for MA Marketing, ***, and called them to ask what the debit order was about.<br> I wasn't given any helpful info, except that the debit order will be stopped and I would be refunded by Friday.<br> How does this happen that people can just take money out of your bank account without any authorization?