Your 'factual issues' are non-existent. There were no policy changes regarding KYC since you joined. Here is a copy of their policy from 11/2019, which has exactly the same text regarding KYC:
https://web.archive.org/web/20191115081956if_/https://www.kucoin.com/news/en-terms-of-useYou're trying to give your own interpretation to their policy while it's perfectly clear. There is nothing confusing about it and you have agreed to their terms when you created your account. The staff technically wasn't wrong about KYC being non-mandatory. As they said in your first conversation, something triggered their risk assessment system, resulting in them requiring KYC information. The other staff members didn't know this as first, but once they checked why your withdraw was halted they informed you about the reason and what information was required.
A civil lawsuit will be an absolute waste of your time and money and it will very likely be striked out before even making it to court.
It is noticeable you are invalidating the necessity of specifics in contract law, and your interpretation of the policy is implying withdrawals will be suspended. This is a mistake you cannot assume anything in contract law, doing so is detrimental as it is required that specifics are outlined otherwise as you are doing any interpretation outside of what was written can be applied simply by one's emotions.
If you wrote this policy correct it, if not do not take personally what others have done it is self-defeating.
Thank you for your insights, you have made me more diligent in my thoughts on this and the motivations for making ambiguous contracts in addition to why I will avoid them in the future.