If true that you had that much in funds on their site I can't help but wonder - WHY?
I saw gamblers to have 10x or even 100x balance in their gambling account. For some it's a lot of money but for others it could be a small part of the wealth they have.
Putting excess money in gambling account is not the right move. We should know that these gambling sites are centralized and in case of any mishap, they can close our accounts and all our funds will be lost if this happens. So better keep our funds with you and deposit only the funds with which you want to gamble.
Wait, which part of bonus feature they were abusing? Can you please quote it from your terms.
I see he wanted the rakeback, you did not have a minimum odd for that so he did not have to worries about it.
Is this part an abuse?
An abuse could be, if he was creating many accounts, claim rakeback for the same deposit from one account to other. Do we have such case?
Having one account and using the bonus is not an abuse at all unless he is found guilt of using more than one account.
I guess they need to clarify what exactly OP violated which resulted in the ban of the account at Rollbit .