OP admitted using multiple accounts, because it's allowed.
It's allowed unless multiple accounts are used for "nefarious purposes". It's unclear what kind of purposes those are, but if a player isn't sure about it or has doubt if what he plans to do is acceptable behavior, he should have asked the casino. OP didn't do that. He assumed it was OK to open multiple accounts to bet above limits set on his older accounts.
Rollbit claimed he used more accounts, but hasn't provided evidence.
They don't need to because OP never claimed having only one account. OP has said he used multiple ones and that his older accounts got limited. Rollbit doesn't need to prove something OP has admitted to.
For more than 2 weeks, they've ignored
my questions. That's not what a honest casino would do.
I agree with you there. And I don't appreciate the silence. But I also don't think OP is innocent and didn't know what he was doing.