As far as I can see in that regard, there is nothing you can do if bc games change their established rules because they are the ones who administer or control games and we are just players who decide whether we follow it or not.
But it cannot be denied the size of the percentage of their referral bonus. But if you think you have a fight or claim against what you are fighting in games, it is your right as long as you are in the right and you have strong evidence against them.
Well, whether it is a change in their games, in their terms and conditions, in their bonuses, or their referral commission percentage, a player or an affiliate can simply do nothing at all, they have all the rights to make any changes they want and casinos also mention this in their terms and conditions that they can always make changes in anything within the platform.
An affiliate who used the casino and earned commissions from their referrals will probably have to migrate to another platform in such a case since they will probably not change their policies only for one affiliate and they probably made the changes for a reason.