Hello Justine,
This is too bad.
When I am not happy with some guests who left the place dirty or did not abide by the rules, I do not post any comment and notation to avoid encouraging them to do so in case they are not fare. I wait until the deadline if there is still no notation from them, I leave the situation as it is.
I did not have such a bad situation, only guests that did not clean the house and left some of their personal possessions they did not want anymore.
What I did for them is that I waited if they posted a notation and finally as they did, I posted mine and was not too severe by giving a 4 stars.
Anyway guests cannot see your notation before posting them and vice verse
And also you can reply to their feedback by posting a public response which will help future potential guests considere the situation with the correct discernment.
Bon courage