Hi @James10,
You could have the guests cancel and offer to refund them 50% IF you can get it rented for the times they had booked for. You could also have them cancel and offer to give them 50% off their future stay OR you could have them cancel and they live by the cancellation policy they agreed to when they booked. They may also have an extenuating circumstance in which case they may get a full refund.
I would keep it entirely through Airbnb though.
Dave
David
Superhost Ambassador ~ Host Club Community Leader ~ Experienced Co-Host