SandBoxCasino uses Owl.games' casino software, but SandBoxCasino apparently operates on its own and works independently from Owl.games. Their admin has stated they have their own userbase and bankroll among other things.
In this case there were no need to bring Owl.Games connected to the case. Owl.Games is just a provider like any other providers for the sportsbooks and casinos we have. OP intentionally wanted to drag Owl.Games into his case so that he can blackmail Owl.Games to recover his fund, I do not see any other intention for him other than this.
In scam accusations, we tend to take the side of a accuser easily but some people takes advantages of it. I think we should look at a case from both sides. OP may have a case but that's against SandBoxCasino.io.