Is someone distributing your software or other copyright content illegally over Internet? It's possible. It happens. If you can prove your case, you have grounds for legal action.
BUT -- before making yourself look foolish and creating enemies, have your facts straight. A reasonable understanding of Internet technology can prevent you from ending up with egg on your face.
Take this situation. I've changed names to protect guilty.
A representative of an online business emailed me saying, "It has been brought to my attention that you have made "something.com" public download files freely available for download by FTP from your web site. Would you please let us know immediately what is going on and what your justification is for doing this."
First mistake. If files are "public download files", then what is problem? Public download files are freely available.
However, since I had never heard of their software, I responded with a request that company rep show me link or at least provide a screen capture of alleged FTP activity.
I received an apologetic email from company rep saying that she could not locate a link to her software from my site. "Perhaps your site has been confused with someone else's," she explained. Second mistake. If you're making an allegation of this nature, know where problem can be found and be ready to present evidence to other party. You look more than a little incompetent if you can't back up your claim in most elementary way.
A few hours later, a third email arrived. This time, company rep accused me of being untruthful and threatened legal action. She then backed up her case with following URL:
Sure enough, "theirfiles" were available for download at this link. And, sure enough, www.nightcats.com is my site domain. HOWEVER, had company rep had a basic understanding of FTP (File Transfer Protocol), she would have understood that a "pub" directory is "public" -- and therefore URL had nothing to do with my site.