Why do you think the SN is fake? If you did a blood test, and the blood turned a dark brown color, that would indicate that the SN is real. The blood turned brown, because the SN worked, and there wasn't enough of oxygen in the blood. You can do an aquarium test to determine the purity of the SN.
I don't know who you are referring to, but you should take anything you read on here with a grain of salt. You get all kinds of people on here, and you never know for sure who they are or what their real intentions are. What reason did they give for failing? One person claiming that they failed over 3 years ago, seems irrelevant at this point. You can always test your own SN.