Personally I've never heard of it and I hate to say this, but it sounds like you got "limited editioned" out of $800.
Is there a chance that you can return it to the place of purchase?
Just for a reference.. $800 will get you a brand name like Century (Schneider) Optics lens that is used by professionals and has been around for many years.
For the benefit of others and if you have to go the discount route... Please stick with companies like:
CAVision - http://www.cavision.com/main.html
16x9 - http://16x9inc.com/
Kenko - http://www.thkphoto.com/products/kenko/index.html
Lens that include the following in the name should be AVOIDED!
Vision Optics, Digital Optics, Titanium, Platinum, Superior, High Definition, Opteka, Superior, Crystal, etc..