Having no formal structure to your relationship will make a suit harder not easier. Sending a dmca take down to the host, google, etc. will probably get the job done, and takes all of 5 minutes to do. If you're unsuccessful with that there's plenty of dirty shit to do. Eli has a decent post on it btw. The message you want to send is that you are better at the Internet than they are and they're going nowhere until you are happy, so it doesn't matter if you are right or wrong.
Course if the other company is smart, they could get you into serious litigation for abusing the DMCA takedown notice.