Do you have photos of the cable in question?
If you find the cable is not as represented my guess is Amazon would help you out.
Well I bought a fake pair of Sky a few years ago from a member with good feedback until I sent my purchased pair to AQ for their inspection. When compared to a "real" pair there was a very slight jacket coloration difference as well as a different feel as to the weight of the conductors. I too fell for a deal that was too good. A legit seller isn't going to give high quality cables away...