Rather than "banning" an entire site that seems to have some spammy pages, why not index only the home page, and flag it in the Google Webmaster Tools dashboard?
Also: are any specific notices or warnings given in Google Webmaster Tools, to inform the webmaster and give some clues about the findings and decisions of your team?
Thanks Matt for taking time to explain things here.
The filleritem.com website is a very simple tool to search for items of a certain price on Amazon. The purpose is to help select an item to fill the gap in the shopping cart to qualify for free shipping. There is no reason for Google to ban this site. What we MAY have here is an abuse of power by Google.