You shouldn't post your email. And welcome. It happens sometimes that the copper doesn't show. Or it's possibly plated. Call it an error and sell it on ebay.
A question, how did the 2 dealers test the coin? Some drop it for sound, some use other means, but I would only want a XRF device which most larger stores would use. Some don't charge if you are a good customer and not a one time customer. Jim