I agree with stanley, if you have faith in god, you do not afried.
the black magic is not identified physically but it can only by the way of feeling
the black magic was not proved by the law matters.
So better, avoid such type of things, if you have that type of fear, I do not blame you,It is about the persons faith
so you do some chantings of Ugra gods like Narasimmha slokas chanting
Sudarsana slokas chanting, Bairava slokas chantings
through the web i can only tel this much