Not everyone likes to read the rules which later creates problems for them, only when they face a problem can they understand its importance. Since this player is facing a problem you should help him in the right way as much as possible. Because it will be good for your platform which will carry positive things among other players. And if this player has made a mistake then you can explain it to him in detail by proving the information.

This is just my personal opinion the rules that's why they got surprised on why they encounter the issue they have but later they discovered that they are already violating the rules on certain casino that's why they are skeptical to accept their mistakes and mostly blame their problem to the platform they are playing on.