15% commision for saying we're sorry it happened?

We've been hosts on the Booking.com and Airbnb platforms for 4 years and everything has been going smoothly. Last year we had an issue with a guest who booked on Airbnb and left a bed in a terrible condition. He wouldn't pay for the damage, but Airbnb replaced the bed and linen at their cost. About 10 days ago, we had a Booking.com guest who burned a hole in an expensive carpet. We contacted Booking.com and supp**** photos. The only thing they're prepared to do, is block the guest. Both platforms charge 15% commission, which should surely include insurance for damage done by guests? I'm very disappointed in Booking.com.