Cancelling a Booking


I called into booking.com about an hour ago to cancel a booking for a mutual guest.  Confirmation number 3693302121.  She asked to cancel and we agreed with no penalty to guest or ourselves.  Can someone take care of this matter.  As she cancelled 1 room on the 16th of March but the system some how did not keep her 2nd room.  At the time we did not have the room for her.  So she asked to cancel