I would ignore and focus on your product. There's not a lot that can be done to prevent this from happening and money, time and resources spent on lawyers with

I would ignore and focus on your product. There's not a lot that can be done to prevent this from happening and money, time and resources spent on lawyers with no certain outcome is probably not as beneficial as directing that money, time and resources towards improving your product. The people who do this tend to be lazy and uninterested in the actual business. (If they had a real passion for it, they wouldn't just clone your public facing website) Thus, they will probably vanish on their own sooner than later anyway.