A couple of things
- Don't lose your cool
- See above
- Don't use the DMCA link on that site. In the words of Admiral Ackbar. "It's a trap!"
- Do a search for your products on Google and Bing. If a link appears to the fore mention pirate. Send them a DMCA request. I done it and it works relatively quickly.
This is the link for the Google DMCA link
This is the link for Microsoft Bing DMCA
Understand software, video, and PDF piracy is semi-organized. The new pirate site is especially slick which is probably why OBS reacted the way it did. However it existed at least a year prior. In addition there are various underground directories floating around that are updated regularly. The links are coded so that they don't show up on the search engines text functions. So the key is to keep those links off of the first handful of pages of search results. And that is not so hard to do thanks to the above links.
It sucks but it not as bad as it could be.