@Yelena30 What is it you want Airbnb to do? I'm sorry you had the nasty guest, but they are now gone, you left them an appropriate review and a response to their review, which makes the situation clear.
You can now click on the flag symbol by the message stream with the guest to report her. I think that will stop her being able to contact you further- if not, I guess you can tell Airbnb she's harrasing you and ask them to block her from contacting you. I know that customer service is bad, but it isn't fake- I get answers to messages I send them.
Then forget about this guest, she's not worth spending any more mental energy on.