@Andreas1314
I have had it done by accident. If accident or on purpose has the Host there is nothing you can do. Only the guest can delete that review.
I know upsetting but take a business evaluation.
1 bad review star amongst many good does not carry a lot of weight for potential guests deciding.
If the reviewer made good comments a potential guest decreases his star rating more.
What a potential guest will look at is the Host's response.
To a potential guest the low stars will look like a guest error.
Nobody plans a mistake, how you respond is like advertising if you make a mistake, this is how I will respond to you.
In this case, I would just write a response looks like you made an error. Comments don't match star rating. We all make mistakes. Glad you enjoyed yourself.