Buyer beware. I rarely buy offline because of such things can go wrong. And how do you know if you have a knock-off?

You tried to save a few bucks online just to have it backfire on you. It's like driving around town trying to save $10 off the listed price, and you just wasted $20 in gas!!!!

Get a LHS (local hobby store) and get them to order things for you. They have insurance, they also will stand behind a lot of their products because of experience. If they carry them, they will have more than one and can exchange should there be a problem.