"Admins can exclude any player for no reason and there is nothing you can do"
Although this is probably true for any online casino, I agree that a little more transparency from them would be a good thing in your case. If they disabled XP contests for you, for whatever reason, it would be fair if they let you know beforehand.
That is not good they must give a good reason to players why he is excluded because he entered the contest in good faith, you have done the right thing posting your experience here but like all the other accusations, you have to back it with proof, without it, this is just hear say or they will accuse you of spreading lies, I hope you can upload the evidence to protect yourself.