oldgoatroper
Roper of Goats. Old ones.
The OP stated that both the product AND the shipping were paid for. That being the case why would you pay for the shipping if it's already paid?
The point in all scams of this sort, ordering products, winning some sort of lottery or contest, or whatever, is to get you to to dip into your own pouch and shell out for something. Be it a 'fee' you pay up front in order to collect vast lottery winnings or an inheritance, remitting an over payment from a bogus check, something. In the scenario described by the OP none of these or their infinite variations seem to apply. Merely paying with a fraudulent credit card, if the scam works, gains the operator nothing more than some free product.
Where's the payoff to the scammer here?
shipping is paid to the sign company, who then is supposed to pay the "shipping company" usually with cash or some form of payment that is not reversible.