They already gave you a consideration when they unbanned your account and they expect some activity from you. Draining their rewards from rains without getting any deposit in return is already a loss for them. They stopped you before it could get any worse. You could be right that they're low on cash but, practically speaking, any establishment could have done the same thing.
What consideration are you referring? This rain bonus is the benefits of a high level VIP. Thenuser has the right to claim it after all his wagered money to reach that tier level. Banning an account for just using his VIP benefits is questionable even though the casino is not getting any from this customer because they are the one who design the VIP benefits and now they are kicking out there customer account just to runaway from there obligation to attract that user to wager huge amount just to reach that tier?
If the OP claim is true, Gamdom should explain the reason for this ban and provide the details in there ToS stating it.