Why have two amounts been blocked from my credit card?

We pre authorize your card at time of booking for the amount of the deposit. This is not debited from your card until we confirm your rental with one of our rental agents. In the event your rental is not available we will contact you to offer the alternatives available. When Cartrawler book your vehicle, a new pre authorization is made for that booking. The initial pre authorization will be immediately released back to your card automatically.