I remember a PSA from my childhood where an Eskimo recieves a swimming suit in the mail (or something equally absurd) that he never ordered. The point of the PSA was that as a consumer, you do not have an obiligation to pay for something that you did not request.
All I could remember about the ad was that it was one in a series and that the messages always ended by asking the viewer to write to some federal agency in Pueblo, CO for more information.
Unbelievably, I googled "pueblo colorado consumer" and found it on the first hit. Gotta love the internet.
http://www.pueblo.gsa.gov/cic_text/m...ome/rights.htm
"Remember, at-home shoppers have the right to...Consider unordered merchandise a gift and be free of pressure to return it or to pay for it."
I'm not saying its morally right, but I don't think they can force you to return.