Fraudulent Booking Blocking my Calendar

I having trouble with a few fraudulent booking through Booking.com. Within the last 48hrs there have been 3 bookings that were fraudulent that we have to wait to cancel and this process blocks our calendar.

Is there anyway I can cancel the reservation through on Booking.com before the grace period ends to update card information. When a new card payment is entered and process resets again. 

Yes, I called Booking.com several times to help with the matter and the representative does not really understand my request to cancel all the related reservation and one call did not call me back at (after the verification process)

Or is there any advice on how to setup my listing on Booking.com so that a reservation is not final until the payment is confirmed with a valid credit card and my calendar is not block. Any assistance would be helpful.