Asked for quote for Duo G1 80LP to P4 0 LP (with a free win in promo) - was quoted the full 17EUR price.
So even if you are 99LP and need 2 games to promote in total (with a free win) you will be charged as if you need 8 games, pricing doesn't match.
Asked for netwins in that case however seller specified he does not provide netwins for duo. Based on the amount of lackluster booster on the community this raised a few concerns if they aren't even motivated by providing worthwhile results if they are paid by the games and not the wins.
All in all, they seem like worrisome and shady business practices, I'd advise care and caution.
Having said that, going by the amount of TBM the seller has, this doesn't mean that their services are dishonest by any means just...unjust!