The same thing happened to me when I bought a Dot from Ebay. I contacted Amazon and they could have helped me if I had the serial number. However, I contacted the seller requesting the serial number and he supplied me with some number but it was not the serial number. I felt I was doomed to be stuck with a useless device, but I contacted Ebay and the seller once more and it was resolved by the seller giving me a refund as he could not help me with the correct serial number.