We were constantly running into this at the hotel.
He told us, FunJet didn’t book the room with them directly. They booked through travelscape.com, which is owned by Expedia.
There are a handful of sites that create URLs like
https://official-sounding-hotel-chain/hotel-name/ for your hotel. Looks very official and vaguely like maybe it's the official site for the hotel. But they have no relationship with the hotel. They then do just what FunJet is doing. $400 is a lot, but I would commonly see over $60 to $120 booking fee. Usually it is a flat fee, so if you stay for a week, you hardly notice, but on a one-night stay it becomes a large fee.
It's predatory.