A double Booking.com booking
I had a ing in place more than one day before a second ing for overlapping dates came through from Booking.com. Booking.com would have been aware of the first ing because they see my availability via my channel manager.
The guest has requested access from March 17, and it isn't available, so it is fairly urgent.
I have asked the guest to cancel, but how do I cancel it if there is no credit card declare invalid?