I understand the concern of the OP. Counterfeiting of expensive audio products is a big problem and you are not going to get a great deal of sympathy or help from federal entities that police this domain. Your options are limited, and I do not think that Nordost bears any responsibility in this transaction. You should know that in this marketplace it is buyer beware - I have even been warned off purchasing a discounted expensive power conditioner here after talking to a person at AQ, and the seller posted a complaint on this site. I would rather get a bad review here than buy a counterfeit electrical product that might malfunction...
Has Nordost forgotton who pays the bills?
Recently I was entertaining the thought of purchasing a pair of used Nordost Heimdall 2 rca Interconnects from a private owner online. Prior to purchasing the cables I did a bit of research on Audiogon to see if anyone had any issues with counterfeit cables. I found no real issues but did read that if contacted Nordost would authenticate the serial numbers on the cables to verify that they were the genuine article. Well, I did contact Nordost and much to my chagrin I was met with the following response from Nordost:
"Due to the overwhelming requests to validate serial numbers for cables being purchased on the used market we are no longer able to offer that service. Serial number verification requests can only be requested by authorized dealers/distributors for cables involved in trade in/up requests"
My curiosity got the best of me so I contacted my local dealer that I have been doing business with for years. I was told by the associate that "He did not have access to this information" Long story short, I bought the cables and I do believe that they are genuine. But the larger issues is that it seems Nordost has gotten too big for its britches. Lets not forget that without consumer there would be no Nordost. The response from them seems so snobbish, not customer friendly or client centered. Most audiophiles are aware that cables have the greatest mark up of any other audio product. Given that and the already overly inflated price for Nodost cables you would think the company would at least give the hint that they care for their customers. Used cables are truly a bargain and my be an introduction to the brand. I digress. My goal with this post is merely to inform folks that if you are considering used Nordost cables and are looking for then to authenticate your potential purchase, well forget about it. They ARE NO LONGER ABLE TO OFFER THAT SERVICE!
Stay well, Stay safe, Stay home and listen to tunes.