[Invalid] Markup Validation of http://www.allgametaxidermy.com/ - W3C Markup Validator
Cynthia Says Report
You'll have a better argument to take to Google once you sort those things out.
The recent way in which Google handles sub-domains (it now sees them as folders) would probably explain the change in your sites rankings. As you have been told, your site has a lot of spammy sub domains.