The TA booked me on the CX 261 of Jun 04. When seeing that I went back to the Tool (how could we live without it?) where the availability was still there for CX 263 on Jun 04.
So I complained to the TA who gave this answer (well in French, I did the translation):
”When I checked the system, the flight (CX263) appeared as full.
As a reminder the reservation system Amadeus is an international system that enables many Travel Agencies to book tickets.
In addition it is possible that, when we did look at the availability, the airline had removed all the quotas to clean all active files on this flight. This is a regular procedure”.
What do you think of this explanation?
Instead of trying to validate a [made-up

] "explanation", could you ask your TA for a copy of their availability screen from Amadeus?