What number is that? Is that your userID or something else? It is a bit weird if you create such a username as it will be hard to remember.
Back to the main issue, can you show how it looks like when you try to sign in to your betcoin account?
Your story is unclear, why did you need to submit document while you have not placed any bets? Did they request you to submit your documents just after you made your deposit?
$300 is just small amount of money for a casino to risk their reputation, so I dont think Betcoin which is one of the oldest casino in this forum will steal your $300.