I actually tried reaching out to them on their social media platforms but they ignored and deleted my comments on LinkedIn and blocked me on Facebook.
There's no way how to check provablyfairness on paying versions too check them out on
https://wolf.bet/ or
https://sportsbet.io/casino or any other popular casino.
Their official provably fair page
https://spribe.co/provably-fair doesn't provide any mathematical methods or script to verify their games either.
Yes, now I see where you have written it, well it's not the main point of your claim but if it's true you're right it's not professional and suspicious. There is a similar thread about Fortunejack on other so-called provably fair games and at least they seem to have contacted the third-party provider offering the game. If it's exactly the same game as the free one(demo) you're right, the game is not provably fair, since we can't independently check the outcomes. They give the seed used and the outcome in hexadecimal and decimal format but they don't say how it has been computed from the seeds and the nonce.