Just to confirm the part of your question. When you say that they don't deal with the Internet, do you mean that they don't sell their products on auction sites like eBay and Amazon to compete against their own agents or do you mean that don't actually want you to sell their products on auction sites yourself?
On your second question, that's an interesting one. I've never actually come across that before myself, but very creative of you to try lol. Is it link spamming, well I don't personally think it falls under that category. I mean you're not spamming anyone, you're advertising a link, so I think they are being quite harsh in their assessment. That said, if they don't want that done, then best not to do it and even though I am not current on what eBay's policy would be on doing that, knowing eBay I would imagine they would have something about not doing it.
Apart from all of that, the situation you found yourself in with the customer buying everything would be played out over and over and over again I think. A lot of people only see what they want to see and you would have customer after customer thinking they were actually buying the product itself, not the information.
I don't actually understand what this link is that they provide to give to your friends and family, that does seem kind of weird to me. Does the link provide the user with cheaper prices than generally advertised on their site?