take down the site and host your best content elsewhere? or better yet fill it up with affiliates, I know it hurts but it's a better move for G to just ban URLS than accounts, it gets my thumbs up for that
Click on "Help" and the third link down on the left hand side is "Contacting Adsense". Follow the links and you'll get to a contact email form.
if that domain is against any tos then you should first of restructure that domain or so. Then only contacting google will be helpful.
I had one that was not showing ads and I figured out it was one I forgot to add the required Privacy Policy to