I've noticed that a site that uses Cloudflare DNS is mirroring my website. I've tried blocking the IP in Apache, CSF/Iptables...no luck. I'm not familiar with Cloudflare but digging more I've found out that it actually masks the website real ip. 2hrs of digging later, I found a tool that brags to get me the real Ip but for this particular site, it says "no real ip was found".
Evidently, I've contacted Cloudflare but they keep spitting the same template over and over, "we aren't a hosting provider but a proxy" bullshit. Long story short, I don't know how to block this website for pointing its NS to my IP.
edit: I've changed the ip of the site to another one (I run a dedicated server and I have a few more). However, while propagating, the infringing site was giving some 404 errors, which made me happy. However, 2 hrs later, it seems to be working fine, even with the changed IP.