I recently dyed my hair brown using Natural Instincts (28 wash) on top of my blonde hair. Well the color wasn't fading, so I tried dying it back to blonde, and the woman at the beauty supply store told me to go one shade blonder than I wanted it and it would turn out the color I wanted. Well I did it, and there was very little change from the brown!

I don't know what to do, I may go back and ask for an exchange or something, because she told me it would work and it didn't, you know? Also, does anyone have advice on trying to get my hair back to blonde?
Thanks