I had a similar situation with Amazon. Used to write lots of genuine reviews, answer Q&As, etc., until one day when they deemed a review of mine "suspicious". They pulled all access to be able to contribute. There was a way to contact them to appeal, which I did and they just said it was still not genuine, whatever I provided to them to the contrary. That was years ago and I still can't do it.

At some point you have to say "your lose" and walk away. You're helping potential visitors but also Google. If they can't be bothered to help here, "stuff 'em". Take you reviews to all the rival services.