In order to provide some context to my question:
I recently rented a car from a company. They required a deposit before handing me the car, as insurance. So I used my debit card, I entered in the card reader and gave my pin. The transaction was completed and the amount appeared in the my bank statement.
Due to a mishap, the car broke down and I was to be charged for the whole amount of the insurance deposit, plus an additional fee. The company charged me the additional fee without needing my card or my pin (or my consent for that matter, as I only saw the additional charge through my bank statement).
So my question is as follows:
What stops them from doing this again? They could have just as easily charged me for any amount, and keep charging me in the following weeks, months...
What is the difference between the first payment (with the card reader and pin) and the secondary charges?