In this case, The casino can simply say the fund is lost and cannot be recovered. They don't have to ask for a $200 charge to recover just $50 which doesn't make sense to me.
I'm not gonna pay attention to the cost, what I think is that the customer will be led to say "I won't pay" because they are actually refusing to help in a subtle way. Had the OP lost $500, maybe support would have asked for $2k recovery charge.
Note: I'm talking about cases in general, it could be that rollbit has other reasons or they do indeed charge that fee at any amount.