i've heard of a similar case as yours with the being being able to look like someone else, use the same voice. I agree on your description, belief that this thing was never human to start off with. Even if you are not of a specific religous faith as the Christian what I find works with me is pray every day, ask god directly for help (so god send out the helpers), if possible keep your vibrations up (One Lights advice to me:), don't think about it (BobJob's :), I use salt too (Traveler's:) and it works, but notice you wrote it did not work for you. Try to get hold of someone strong enough to sense through all the filters this thing is going to display if, when in contact, not someone who is too naive. The case I heard of it was in a particular home and not outside of it, don't know if you still stay in the same home, if this follows you around. I've had troubles with poltergeist activity, sometimes not sure if I've done it myself, created it through suppressed or blocked negative emotions, or temporarily spirits, energies.