@Corinna76
Well, unfortunately, this is typical. Since the guest denies it, you'll be lucky to get anything.
I've put my energies into guest screening before they book, and scaring them away before they book, if they seem risky.
It's worked pretty well so far, and minimises the need to involve Airbnb, which, in addition to the risk of not getting any relief, because the guest is confronted, there's always the risk of the guest writing a scathing review and/or issuing some complaint of fabricated atrocities you committed, and your listing being suspended and future bookings cancelled. In addition to eating the damages.
The best remedy is always prevention. Keep Airbnb out of it, if you can.