I don't want to pick on anyone here, because poor theological training is a characteristic of HAC. Concerning heresy:
Titus 3:10-11 teach plainly that a heretic is unsaved "A man that is an heretick after the first and second admonition reject; Knowing that he that is such is subverted, and sinneth, being condemned of himself."
Because there is no condemnation to them that are in Christ Jesús, and because that which is born of God sinneth not, a genuine Christian cannot remain a heretic. Heresy refers to doctrines that prove that a person is lost. Denying the Gospel, denying the Deity of Christ, etc., are heresies, and a person who clings to those doctrines after being admonished is not born again.
Baptism, eternal security, Calvinism, speaking in tongues, church government, the Rapture, which translation to use, etc., do not involve heresy. A genuine Christian can be mistaken in these áreas. Don't let somebody scare you into or out of a doctrine with threats and accusation. God hasn't given us a spirit of fear. When God wants you to change your belief, the Holy Spirit will teach you the truth.