If it has been 3 weeks you can go on GunBroker.com and follow the links to the help section for buyers.
They have a form that you can check-off the area that matches your problem.
Check the box for "sent money---did not recieve product."
They will forward your message thru their server. It may help to get the sellers attention.
Feel free to e-mail me direct, maybe I can be of some help.
edited for fat fingers...............