I am level 7. My problem is i have tried to fill a black soul gem about 4,322 times over 3 real days with no luck. I have researched every forum I can and tried all the suggestions. I have gotten as close as possible before casting soul trap, have cast at target with full health and with low health, have tried with just spell and no weapon, and with spell and weapon, I have dropped all other soul gems I was arrying except Black Soul Gem, I have even made my companion wait so that I make sure I kill the target myself. I have fed right before doing this to insure that wasn't affecting the spell. I never see the purple glow on the target that everyone mentions after casting the spell. Unless someone can assist, I guess my only option is turning into a werewolf. I believe I will still need to fill more Black Soul Gems in the future so that wil only help me be cured of vampirism, but not filling gems.