There are multiple points of authority on this question, not the least of which is the Bible - which defines who and what Christians are. The cults have their own philosophies which they follow and they dab that in Christian imagery for their own twisted purposes - chief of which is to mislead people. Not unlike evolutionists - ya'll just don't try to pawn yourselves off as Christians - you just try to excuse your belief system by saying "well some christians believe it too".
What is your authority for citing the Bible as an authority? What would your authority have been if you lived in 300 A.D.?