The trouble with flights is that sometimes it's true, and sometimes it's a booking scam.
or just that their share of seats has been sold.
When this happens, another agent may still have seats on the flight for sale - a bit like theatre Tickets!!
As for the Mythos, I gather that it's being sold as a going concern - a business, so T/Cook should honour the bookings,
we would hope!
Thomas Cook may choose to place people elsewhere, but I would be screaming if it was another resort.
Try not to let these big operators bully you into anywhere else -
they always have the option of renting other accomodation in S S!!