I am looking at their FAQ and the part you mentioned about alt-accounts. Yes, they do allow it, but you are forgetting the most important part of that rule. You can use alt accounts
as long as you have not created another account for nefarious purposes. https://rollbit.com/faqAnd that's where it's not clear. How would they are going to define nefarious purposes. It can work for both side. Advantage for a casino to abuse if the case of the OP real, on the other hand users will abuse too. Besides, I don't like the fact they said he was depositing the money back (That's what I think abuse from the casino side).
If your first account got limited, and you aren't allowed to place bets above a certain threshold, creating multiple accounts to avoid this restriction can be seen as a "nefarious purpose".If your betting limit is $1.000/day or per match, that doesn't give you the right to create 4 more accounts, so that you can wager a total of $5.000, for example. It might sound harsh, but that's the way they are going to look at it. You are abusing the limits placed on you as an individual.
If all looks correct then why would a user will create more than one account at all?