Does it hurt you in any way? If not - I would just leave it alone. Google can tell a copy from original. I tried to search some arbitrary text from your website

Does it hurt you in any way? If not - I would just leave it alone. Google can tell a copy from original. I tried to search some arbitrary text from your website - there is no trace of copycat in Google SERP. What striked me, though, is that a copycat website is waaaay faster than your original. If I were in your shoes, I would invest my time and effort into speeding up the site. Unlike hunting some script kiddies, that will bring palpable benefits.