My experience with Rollbit is great until now, so it's definitely safe to deposit and gamble in this casino. Any casino can cancel or void your bet, depends on case by case. If you're breach their terms of service, they have a right to do that.
What did you mean about can verify for a month or more and ask for different documents?
My general impression for Rollbit they're trusted enough and they're not really strict.
They will verify your identity for the withdrawal process not for a month specifically because they have your submitted documents but yes if you are playing on Rollbit you can trust them in most things like deposit, withdrawal and promotions for the players and I also have smooth experience gambling over here.