To effectively curb copyright violation first you need to identify your potential customers who are willing to pay, cater for their needs instead of suing them because you failed at business. Then you've seperated out those who are just freeloading scum from those who are willing to pay and can look at encouraging those left to pay through other means such as education, etc. or alternative means such as advertising revenue. Failing that they are fair game to feel the hand of the law.
Suing your customers because you failed at business is only going to end one way.