What we did to displease this fellow we can only guess. We don't get negative reviews very often, and in those rare cases it is usually because we have failed in some respect to communicate or otherwise attend to the guests' needs in the way we normally do. Like forgetting, for example, that a guest is vegetarian. Such criticism is deserved, and we take it to heart.
Expectations can play a role, too. Once or twice we have had people disappointed that there are no televisions in the house. Once we even had a guest who insisted that since we had five-star reviews, that meant we HAD to have a swimming pool or at least a hot tub. I am not making that up. There's not much we can do about that, except strive to make our descriptions as accurate as possible.
But in this case, the guest made no indication that he was unhappy with the absolutely spotless Victorian room he rented, or the large breakfast made with mostly organic, locally sourced ingredients, of which he and his wife ate every bite. They did get served a cold coffee in the morning -- an error in the kitchen by a young girl helping us out -- but we replaced this right away.
So that he then proceeded to slander us to Airbnb came as something of a shock. He claimed our B&B description was inaccurate because the 1860-era structure was somehow "more vintage than described". He claimed the soft, hand-pressed pressed 800-thread count linens were not clean, that the freshly shampooed carpet "could be cleaner", and that the toilet, which is cleaned and disinfected every day, was "unsanitary."
While there's always a chance we will miss something, there's zero chance we would miss EVERYTHING, as this guest claimed to Airbnb. We spend hours cleaning our beloved home, and every room in it, every single day. We can only conclude that he intended to damage our reputation for reasons that have nothing to do with our home or the services we provide.
I would be very cautious about allowing this person into your home.