@Ariel202 Yes, they can continue to message you after your stay. You could leave the review, and then after that go to the host's profile and click on "Report this profile" at the bottom. When given some choices, choose abusive or hostile, then say why and say you want to block them.
But you can also go directly to Airbnb (see first page of Help section for all the ways to contact them, but if you're on Twitter you can send a direct message to @Airbnbhelp). If the host has been inappropriate Airbnb needs to know. Any kind of interaction that makes you uncomfortable should be reported.