guest relocation charge

HI, we had a guest book our holiday home at 10pm one night expecting to arrive straight away. We've been charged a relocation fee from airbnb as we were unable to accommodate the guest. Now I'm battling with them to try and get this fee waived on the basis that we were already in bed asleep and it's unreasonable to expect us to provide a 24 hour service!  Anyone had a similar experience and what happened?