A guest booked for four nights, stayed two, then canceled. He claimed he canceled by mistake, but he didn't attempt to reinstate the booking and I didn't allow him to return without going through Airbnb. Meanwhile Airbnb canceled the booking and I have not been paid, even for the two nights he stayed. Airbnb has offered no explanation. This seems like an obvious scam to stay for free, and I ended up losing four nights of income. Is this a common scam?