We are also booked with Delta. We also logged on the Delta website and have our seats reserved. The problem is that until Flights by X pays for the flight, our seats with Delta can still change. We are listed as confirmed flight with Delta but until we are ticketed those seats can change at any time. Flights by Celebrity won't ticket our flights until about 30 days out. We have paid our final payment but still waiting for Celebrity to issue payment to guarantee our flight. We can't even upgrade our seats until we are ticketed.