There is no such thing as patient abandonement, outside of, perhaps, an acute care situation--i.e. when a physician refuses to treat someone who has been a patient and needs treatment right then. Otherwise, doctors are, when you get down to it, business people; they do not need to serve or treat patients who are uneconomical, who are troublesome or abusive, or whom the doctors simply don't want to treat. (Doctors are private citizens; they have a right to not treat anyone they don't want to treat.) Therefore, assuming the doctor did not stop treating you when you actutely needed treatment and his failure to treat you imperiled you health, a doctor may refuse to see you as a patient--especially over a "vigorous" billing dispute.