My forumotion design has been copied by another forumotion forum

Here is my forum: http://emperor.forumscorp.com

Years ago, back when it was PHPBB2 it had the same layout as http://pep9.nstars.org today. They copied it and didn't ask for my permission.
I'm not sure how to deal with this it pisses me off, I get no credit despite the fact that I created the design. The blue text, hover text for highlight, forum category logo, etc. They just put some extra features to make it less obvious, but it's very clear to me!

Philippine Exotic Pet Owners Community (pep9.nstars.org) has not replied about anything regarding this matter.

Even the marquee scrolling from right to left has been copied. I'm honestly fine with that, but stealing mostly everything I made is not cool.

If you don't believe me, visit my forum. Roll back to 2013-2014 you'll see my PHPBB2 layout from before.

This is a big deal for me, it wasn't easy to make this kind of forum design. Very unfair, especially the fact that their forum has more registered members than mine.

What I don't understand is, first why didn't he ask for my permission. Second I would be happy to sell them my forum if forum design duplication was their purpose.

Nevertheless both of our forums are dead (inactive) now. But I still don't know how to deal with this.

These guys should be sued. I don't know how they copied my pictures and content (probably source code) without the direct CSS code. But this is totally wrong.

The theme is on Hitskins: http://en.hitskin.com/search-a-skin/emperor-scorpion-forum/197616 . The forum you linked looks different from your forum.

My forum now is PHPBB3 so of course it looks different. Lyrroth is my alt account, I remember now. I did share this on Hitskin before. My bad.
I wish I didn't upload it back then, but I guess I can't remove it now. Wish there was a credit from the website it came from though.