I have the same thing going on at our place. We are in an Unincorporated county area with NO town or city. The county manages all our needs. But like many rural people in the US we are required to use the city or town closest to us in our address so the police and delivery people can find us. We don't even get mail at this address but you must have a town or city.
So since we use that city/town for our address BUT ARE NOT in that city/town AirBnB automatically is charging our guests the amounts charged for the city/town INSTEAD of what the County charges. I have a license from the county. I have gps coordinate that will locate us outside of the city/town and yet after 15 emails through customer service they won't correct it. I am now being completely ignored.
I am a long time (since it started) Super Host that loves AirBnB but this company has been stealing Occupancy tax money from our guests for many years and I can't get them to stop. They are collection money for a town/city that does not want it from us and that knows we are not in their tax jurisdiction.