@Deb3497
It's a delicate matter and a grey area.
Airbnb will say that the host must honour the price.
However, it isn't airbnb's property. They can't force this, so no cast iron guarantee.
Hosts - without excusing them - can make errors when setting pricing, or become inattentive as the calendar automatically opens up or inadvertently fudge the amount of discount applied.
Perhaps if a host made an underpricing error, they might decide to 'suck it up', but for a booking of three months duration in high season, this measure is likely to be unpalatable.
Sure, you can try to renegotiate with the host over price and duration to try to come to an agreeable outcome as a pragmatic solution. Contacting airbnb helpline might provoke them to mediate and in turn to contact the host to urge them to 'do the right thing'.
The host will have to option to cancel the booking, probably without penalty if it was an instant booking, which will now hang ominously over your booking. Airbnb only help rebooking at their discretion under certain stress conditions.
If it were me, I'd probably consider asking the host to cancel this booking and look again, perhaps entering into pre-booking correspondence with an alternative host for a reliable landing.
On a practical level, don't cancel the booking from your side, you would be on the hook for the first payment.
You can amend the booking duration without host approval, check the guidance first for nuances.
