I think going to the BBB is quite extreme.
If this is the kind of thing people use the BBB for, its no wonder they rarely take any action. You guys were trying to take advantage of their "mistake" in the first place so don't act like innocent victims
. It seems kind of obvious that it was an error considering its a high demand item and they would have been selling it at a huge loss.
If you really feel like you're being scammed you can always have your credit card company block the charge. Do that and then keep the item until they agree to pay for return shipping.