@Andrea4538 as @Emiel1 and @Mike-And-Jane0 have pointed out, the host's actions constitute review extortion. If you want to report the host, you can open the message the thread, locate the message where he demanded a positive review in exchange for money, and click the little Flag icon to initiate a complaint. I don't know what the end result of that will be; if there have been other complaints, the host might get de-listed, but maybe it will just vanish down the memory hole.
What most likely won't happen is that you get the refund your host tentatively offered you. He has neither an incentive nor a contractual obligation to throw money at you. If the state of the property was so poor that you were unable to complete your stay, you would have been entitled to a refund for the nights unused after you relocated (granted, it's really hard to get through to CS these days to enact that).
But a reasonable complaint can only have two goals: a) the host make the necessary repairs to fix the problem, or b) you are able to cancel the booking and leave the property. These days, a lot of people seem entranced by an imaginary third option, in which you get a free or discounted stay by complaining about something that's no longer possible to fix. That one is a dead-end street.
