This seems to be happening more often with Airbnb - happened to me on both of my two most recent bookings.
First one, booked, booking accepted and paid for. Owner emails to say he put the wrong price. New price was almost double so I refused his offer. Airbnb said I should either accept the new price or the owner would cancel, despite me pointing out that their own policy says hosts cannot change prices after a booking has been accepted.
As I refused to pay almost double and the original price was reasonable not an obvious pricing error, the owner cancelled.
Made another booking and the same thing happened! This time Airbnb said that changing prices after a booking was accepted was unfair to guests and was against their policies. Odd how they took a completely different approach with the first booking though and completely ignored their own policies! They told me not to cancel as I would still have to pay for 100% of the first night and 50% of all the other nights even if the host got a new booking for those dates. If the host, rather than you cancels, then I think there is some kind of penalty, eg they cannot relist those dates for booking? Airbnb also sent me links to a few alternative properties, but not one of them was even in the same city and one was another city, over 2 hours away, so useless. They then closed the case despite it not being resolved. Contacted them again and they asked why I hadn't checked in! Referred them to previous emails and asked for a refund. Eventually they did refund me.
Obviously I had by then booked somewhere else (NOT via Airbnb) so that I had somewhere to stay.
Sorry, that doesn't answer your question, but don't trust Airbnb and screenshot everything as evidence.