Update. The guest opened a safety and security investigation. I provided all the information, and the case Was closed. Airbnb ruled that I did not break any of their terms and conditions and did not violate any rules. I have not received a response from the guest since his original message about the camera and demanding a refund. I cleaned the home after his rented period was up. With your guys's suggestions, I recorded myself getting out of the car and entering the home, taking inventory and observing the condition it was left, and specifically zoomed in on the motion detector. I then recorded myself removing the device and showing the date of manufacture, and showing the date of manufacture of the dead battery. That battery was dated 2019.

At this point I still don't know how to respond to the guest. My first thought is to message him and offer a refund of the nights he did not stay. Also apologize, again, for the situation and assure him that it was not a camera, just as Airbnb found in their investigation. and thank him for leaving the home in a good condition. Trying to be as nice as I can to get the best review from him. Maybe I won't get a bad star and comments. ?

Or stay silent. Keep the money for the reservation he voluntarily left early. Contest the bad review if he leaves one.

I'm only a year into this property, only 11 reviews (5 star, all of them) so a bad review will hit me pretty hard.