Seeing the reviews at first I was inclined to believe that they were legit. However, upon seeing the users' profiles who left some of those reviews, I've decided that they are most likely a scam or at least engage in the shady business practice of paying for fake reviews.
Here is one of the users who left a five-star review of their service. Despite having uploaded an avatar to look real, this person only has one review - that service - and he has upvoted all other positive comments about the service as well as downvoting negative comments.
If possible, use a trusted escrow. The chances are that they will not do that, in which case don't buy.
TL;DR: unknown company creates entirely new miners and engages in shady business practices. Possible/likely scam.
No wonder why your profile trust is -2
We are in business since 2016
If you want PM's from new users go to Profile and enable " Allow newbies to send you PMs."