I would just call the unfairness a situation where I was really "unlucky", meaning that I was unlucky enough to be one of the many gamblers who fell victim to the cunning of the casino, and there is nothing else we can do but accept the situation we are in, and however the acceptance factor within is indeed recommended when you are involved in gambling because this is a preparation for the bad impact or defeat that occurs at the end of the session that can never be avoided completely.
On the other hand I think we can never measure whether the game is fair or not because you will never know and can't measure that what you are doing is right or wrong when you are in the middle of a session so this is what makes when you expect to win with everything you do but the result is losing, after all gambling is a gambling activity that has no certainty whatsoever about the outcome, so I can't claim that the casino is unfair except for technical issues such as account freezing or withdrawal process failure.
You're right about IT difficulties. These are quantifiable fairness measures. What about subtler aspects? Example: win-loss patterns. Are they random or more?
I'm not saying that we should ignore fairness because that's certainly our right as an audience or a customer of the casino, but what I'm saying is that you can't reach out and get full access to be able to get or collect fairness from an online casino when something like that happens outside of the issue of unlucky losses. So it's a good idea to suggest to anyone to first assess or look from various sides about the reputation of the casino you want to enter, try to make sure they can be trusted, because this is also for the security of our involvement to avoid some technical problems or unfairness outside of the general risk acceptance problem that exists in every gambling..