We are not experts on gambling cases but what you have now could or have been experienced by gamblers here because we are all gamblers, and we are on the same boat when it comes to KYC and proof of income, so its better that you complete all the details and be specific on what the problems and what's the name of the casino and what type of documents they are asking.
I asked the name of the casino and the specific documents because there's a possibility that if the casino you're playing is popular in the community, there's a possibility that some of us here encountered the same issues from the casino you're playing, so they can guide you on how to proceed.