If I were you I would:
Move to a new hosting company
Clean up every little thing on the site. Look at the google webmaster guidelines and make sure you do nothing they don’t like. Don’t just rely on one person’s input, gather info and learn.
Get help with your HTML and clean all of that up.
Then file a reinclusion report. When you file for reinclusion you have to report every little thing you may have done wrong and tell them you fixed it.
This is assuming you have a penalty, which may or may not be the problem. But it’s a place to start.