Lot of good suggestions already. I am not sure if you are interested in contacting the perpetrator directly and asking them to stop this but I did a little research for you.

looking up the whois info, it says that the registrant's email was bgrf@ymail.com

When I put this email in google, I came across another spammy site called baklinks.blogspot.com. This site asks you to swap back links. At the bottom of the blog post, I found the name of the person "Naveen K R"

I then looked up google with "Naveen K R + bgrf". I was able to find a site he (probably) runs called www.zokali.com

More googling combos, I finally found his linkedin profile and his name "Naveen K Ramanand"

https://www.linkedin.com/in/krnaveen.

May be you can contact this guy directly. Seems like he is the one doing this or at least he knows who.