@Marcos-And-Victoria0 Sorry this happened to you. One thing to know is that there are many reports of listings by big property management companies doing such things and inconveniencing guests in other ways. You are generally much better off booking with a private, hands-on host who looks after their own place, or has a local co-host, as those listings have a personal stake in being respectful of guests and earning good reviews.
I don't quite understand, though- you booked 2 years ago, then moved the dates, 13 people booked flights, without you touching base with the host since making the date alteration to make sure all was okay for your reservation?
Airbnb listings are non-transferable- so when there is a change of host, it's a brand new listing- like any business, the new owner has no obigation to run things like their predessesor did, nor to charge the same prices. So it's the original host you booked with who handled this very unprofessionally, i.e. the management company, not the new owners. If the pproperty was for sale, they shouldn't have been taking bookings far in advance, and you should have been notified of the situation.
And a host can't just transfer pending reservations to the new owners- that would be disrespectful to guests, who presumably booked based in part on the past ratings and reviews. A new host may not keep his properties clean, or well-maintained, or deal nicely with guests, so guests need to be given the choice whether they want the booking cancelled and be refunded, or take a chance on a new owner with no reviews.