Certainly in India, BKism will exploit anyone coming forward believing to be under the effects of curses and black magic ... but really all they would be doing is using those beliefs to steer the individual towards becoming a BK.
Fear and superstition exist in many 1,000 of times more than any actual occult phenomena. The less you fear or believe in it, the less it will effect you. There are huge industries exploiting those fears where no real effects exist.
I would accept that many weird, wonderful and currently unexplainable nasty psychic influences happen.
But, as Pink asked you, why do you think you might be under their effects? One has to remove all the simple, obvious and logical likelihoods first.
If these people are near you, you could speak to them ...
Spiritual Research Foundation. It seems to be their kind of thing.