trouble is, I still don't fully understand what recourse you DO have if you find yourself being ripped off but have not filed paperwork.

If anyone does know the answer I'd love to hear it. I'm sure you can ask them to remove the content, but if they refuse then I'm not sure what the next step is. I think you can actually file copyright paperwork retroactively as much as 5 years after you originally published the content and THEN go after the infringer.... but that may or may not be the only/best option.