It is unfortunate that you have found this forum under these circumstances but, maybe it is a good thing.
This thread is a result of the mindset between collectors, we do not want to see any other members paying big dollars for something that is not what it should be, and yes, unfortunately, emotions do come out when anyone that has bought a fake is involved.
I can only welcome you as a new member and suggest that you post any helmets that you are thinking of selling here so that our knowledgeable members may help authenticate them for you. This way you can also put on your add that they have been authenticated on a public forum. Surely this can not be a bad thing.