We do have an area for filing reports on users... it's the Cheating & Abuse section of the forum. Found here: http://www.conquerclub.com/forum/viewforum.php?f=5
You'll want to make sure you've reviewed the Community Guidelines http://www.conquerclub.com/forum/viewtopic.php?t=7785
so you can state clearly what he's guilty of. Fair warning, CC has a pretty wide tolerance for in game communication...
All that said... your first line of defense is to open the user's profile and click on the word "Foe" - this will block communication from them as well as stop them from joining any of your games. That way.. regardless of whether or not CC chooses to do anything, at least you're protected from further interactions with that user.