SoftSwiss is a big partner of Wazdan and they are interested in getting truth.
What makes you trust SoftSwiss while you don't trust Wazdan? Is that because Wazdan didn't rule in your favour, and told you to pay the player?
But now there is no any proof of it's fairness
That's not how any of this works. You're supposed to know up front that the games you offer are fair. You don't need to prove that. If anything, you'd need to proof it's not fair, but you can't prove that. What you meant to say is: "But now there is no proof that it's not fair". In other words: pay the player.