Hello,
I hope Gumroad has given you an explanation, but I know this sounds ridiculous but hear me out. The last few movies I posted did not show up on the store page. A fan knew I posted them because of Twitter, and he alerted me. Try going to Settings, Profile. Then when your movies are showing on the right side of the screen, choose Preview. I think Gumroad has added a new Filter system, but testing was not done or did not catch that new movies are not listed.
After you go to Preview, go to the three dots on the left side of the screen and choose Products. Your videos will show with or without the check boxes. Hopefully your stolen videos are unchecked. After you check them, they will appear, I hope.