When you buy on the net, you must know you have a complete protection of what you buy, with one European Directive:
You buy to a dealer one piece and when you have it, you see one problem. You must immediatly send back the piece to the dealer and ask your money back.
If he don't want and propose one credit on his shop, you must tell "no" and contact the Juridical service of Visa or Mastercard.
They contact the dealer to have your money, if not, they can file a complaint.
I know this becaue a friend had a problem with a dealer, now, it's finished. Why? because with a complaint, the dealer can see his Visa count closed.....