Too familiar with this casino...
You tried this casino using a promo code that was distributed, after that you won and the winnings could not be withdrawn because you had never made a deposit?
Usually casinos will ask for a deposit, and withdrawals from promo codes are not as full as you can withdraw... but anyway this casino has a good reputation, you should not deposit a certain amount of BTC because it is too big, it is better to leave it and choose another casino that has a good reputation on the forum.
The scheme is a design scam that is already known, and this is not like the normal deposits to claim bonuses and if it about deposits to claim bonus, the casino could have asked the player to make the deposits First before he can claim the said bonus but in this case he was just offered free money, gambled with and won before being ask for specific amount in Bitcoin, this is pour exit scam attempts on selected victims.
Unlike the regular gambling sites who operates with term and conditions for bonuses, this particular site did not mentioned any condition that you must make deposits after you win using bonus claimed from the site, so that is another point to pick from the whole issue and I have to advice the ops that he should run and avoid this casino by all means.
