All Curacao licenses are useless. Yes, on paper they are real licenses but gambling companies only take them because they are super cheap and the licensor don't ask much questions. If a player wants to submit a complaint to the Curacao licensor about a website, then the player will get no help at all. It's a complete scam.
Well, anyway, Curacao at least has a form to send a complaint about an online casino, which users can make, but here's how to make sure that the casino has a license with which there is a dispute, except for the certificate that it provides, it turns out that there is nothing else.