I'll repost what I posted elsewhere.
But first.. So you paid someone, got scammed, and they scared you, threatened you, possibly black-mailed you. I'm sorry to hear that. It is indeed a scary place to be.
Christopher Hyatt seems to have had this experience multiple times. There are groups that will have you do blood sacrifices, sell your soul to the devil, etc. I don't have anything to do with these groups or I make it clear to them that I will not have anything to do with their practices. I'm not a fan of Christopher Hyatt's writings, but if you are in earnest, and you really have made "Pacts with the Devil" then looking into his books might be the solution for you. If you really need help feel free to contact me on my facebook page or here and I will see what I can do to help. I very quickly skimmed this post.
This being said.. There are scam artists out there that can I indeed inspire fear. They or may not have any magical power. But your best recourse is probably the police unless you, yourself have something to hide. But I know from my own experience that when I'm paranoid I can't go the police. So I understand. And will try to help.