Well you can see the screenshot from Telegram, in which he asks for money to provide an 8+ review instead of 6.4 or whatever.
Yeah I see it, but that doesn't look like a threat or extortion scam to me.We all know how most rating websites work, you pay more and you get higher rankings, nothing new about that.
The extortion also came in form of fake review.
They're giving OP a preview of the draft they'll publish in case OP refused to pay. I peeked at their review page and see that there's no article yet about BKS, so I think the screenshot given by them --and from them, posted by OP here-- is indeed the draft.
Given its a false information which will be published if OP refuse to pay, I think that can be considered as an extortion and not how most --honest-- rating website works.