"First of all the guy made the site illegally by copying files from "affiliate"."
Not surprising.
But the thing you need to understand, the next time you think about buying a "website", is that there are a bunch of different things involved in "buying a website". A copyright does not get transferred simply because someone transfers the copyrighted material, and promises that he won't sell it to someone else. Looking through the auction description, there is nothing that indicates what rights the seller intended to transfer, and it doesn't sound as if you received, or asked for, a signed copyright assignment.