[header] How to penalize the unlawful use of your music [title] Find contact information. [step] Before you can engage the person or company unlawfully using your music, you must first determine who the responsible party is and how you can get in touch with them. In some cases, this can be a fairly difficult endeavor. 
[substeps] If the unlawful use is taking place online, look for a name or contact information associated with the owner of the website itself. The website's whois information can let you know who registered the domain.