I don't know if there's any legal or ethical grounds I can pursue here, but if anyone knows please let me know.
AFAIK, every website with an affiliate program has Terms of Service, where it is clearly stated that the website owners can change the rules of the affiliate program(including commission rates) anytime they want. Joining the Affiliate program means that you accept those Terms of Service. Good luck going to court with any claims.
I don't know about any affiliate program in the world, that would agree to discuss any changes of the commission rates with their affiliates. If you don't like the new commission rates, just stop promoting BCGame and try to find a casino with a more lucrative affiliate program.
Its not a legal question in my opinion, rather a loyality question. They changed it without letting us know by still showing us the old commission rate on their website (35%) - Eventhough its only 9.8% right now.
I earn now more on Nanogames then on BCGame (Nanogames is a clone of BCGame) - Where I only have a third of my referrals invited yet. That's kinda funny.
Its a serious sign of money problems. They obviously had to change stuff to adjust to their money issues. A pre-stage of death (just my opinion)
I wrote coco (BCGame creator) and let him know my opinion. The message is still unread since a week though.
BCGame will die soon or later, its showing clear signs of a breakdown. I will certainly not advertise BCGame anymore.