Hi @Michelle4016
Was this a long term stay? Lots of scams with that where guest pays for first month per Airbnb's long term stay policy at a steep discount. Then when the next payment is due on the 1st of the next month, Airbnb is unable to collect as the credit card is no longer valid (guest removed it, or fraudulent card).
If not a long term stay, it could also be a stay booked with a stolen credit card.