I've reported this thief that stole my code, and is selling it in a game on itch.io 3 times, haven't heard back from any of them yet. What does it take to get an answer? Is there a secret form somewhere I can start my copyright take-down claim with?

If using the regular report form had no effect, you can file a formal DMCA complaint as detailed in the Terms and Conditions. Hope this helps.

Thank you, I've been searching for this for weeks, something this important should be included in the website's footer.