Biosilk Help!

I recently purchased Biosilk's Silk Therapy Shampoo and Conditioner, and I feel like it has wrecked my hair!  I've always heard about how great Biosilk products are, but since I started using their Silk Therapy shampoo and conditioner, my hair has become very dull, and it gets very greasy very quickly.  Prior to using Biosilk, I used Pantene's "brunette" shampoo and conditioner, and it was great.  My hair was always very soft and shiny, and, most importantly, it felt clean!  But I really want Biosilk to give me the results that everyone always raves about!  Is there something I should be doing that I don't know about or did I just get a bad product??