I bumped over here from waterofthemoon's post. I had the same thing happen to me with Cafe Press a couple years ago. The WB/SPN claimed copyright on a silhouette of the Impala with the text "rock music plays". Not only was the silhouette vague enough it could have been any type of car, the phrase "rock music plays" has never been used in connection to the show. I did the same thing you did, wrote an email back asking for more explanation, and received the same canned reply.

We make these products to promote the show, not to line our pockets with buckets and buckets of cash. It made me so furious when I saw other merchandise with pictures of Jared and Jensen actually ON IT that was still available for sale. The double standard is ridiculous. I don't know what we can do about it, but thank you for getting it back onto the fandom's radar.