Negative review / I cannot reply to it.

First of all, good afternoon to all.

I've got a very negative review from a guests. He gave me 1.0 when my average is 9.4. It's quite normal to get 10.

The thing is that the "guests" mistreated us, I don't want to give you the details but I can tell you that I reported his misconduct to booking, but they did nothing about that. 

My problem now is that I have tried to reply to his negative review but each of the four answers have been rejected by booking. I promised you that I have followed the rules, I didn't include personal information, I didn't use bad language and so on. But any of them was aproved. 

So here is my question, what can I do?  I have contacted booking by different means but their answers are... we cannot delete negative reviews, and edit your answer again. 

No solution.