Gaming Club Casino - Confiscated winnings without explaining anything

I registered in Gaming Club Casino on April 12, made my first deposit of $100 got a welcom bonus and lost. Then I made the second deposit of $100, got a second bonus, played for a few weeks and won. I carefully read the terms, I did not violate anything. I fulfilled bonus requirements and withdrew $1320.
They asked for notarized copies of the passport, I sent them. After that, on May 3, they confiscated the winning including deposit and blocked my account without explaining anything.
It seems clearly as a fraud!
Dear AskGamblers Complaints Team, help me please.