Forward me one of the emails you've received, to
webmaster@triumphrat.net.
To answer your question, the "Contact Seller" link doesn't work unless one is registered and logged-in. When they click on the link, it shows their email address - but not the seller's.
However, when the seller receives the email, they are shown both email addresses.
If I moved the "Contact Seller" function to the private-messaging system, you wouldn't be able to know their actual email address.
This helps to confirm validity, but it doesn't stop someone from registering and writing the message. However, we can block them from accessing the site.
Hope this helps,
