@Tam2009 Something similar happened to me once as a guest. I had a place booked during a big event, and as the date got close and basically everything in town was sold out, the host requested that I pay a drastically higher rate because she'd made a "mistake" in pricing. I asked if she was willing to honor the booking for the price we'd agreed to, and while she didn't explicitly refuse, she made very clear that I was unwelcome.
I contacted Airbnb to advise - long story short, they recommended I cancel but refused to refund the service fee. In hindsight, I should have pushed the "trust and safety" rhetoric when asking CS to grant the "neutral" cancellation that @Sarah977 describes.
Like @Colleen253 , if I were in your situation I'd also be concerned about the possibility of a last-minute cancellation, because the host has already shown himself to be unreliable. With a group of 12 you need to be able to trust that the rug won't be yanked out beneath you. If it were possible to get out of the booking without losing fees, and a good alternative was still available, that would be my first choice. But I'd also look through the host's past reviews for some clues - has he established a solid reputation over the long term, or just lightly dabbled in hosting?