If this become a concern I think Rollbit will sort it out. If they failed to then it is what it is. And I think it is not on my part to be too concern on that, it would be the owner, since those who have fund on Rollbit can just withdraw their funds before it become a trouble.
If you look at the thread below on that link, it appears as though Rollbit is not licensed anymore. I think they need to address this asap