I have a guest who says she has booked my cottage and she showed me a receipt for the booking. The booking does not show up on my calender so those dates are affectively still available. Alexi
I would make sure you didn't get the confirmation email from Airbnb, and I would definitley contact them just to be sure. If you don't have a reservation with the guest confirmed by Airbnb it's probably a scam or a mistake on the guests part.