Are the first five years the most important in a child's life? What if your partner continuallyundermines you?

Your ex partner undermined your parenting, told the daughter not to listen to Mommy because Mommy was "Stupid" and the child was continually told this over and over again so she believed it and learned instead how to manipulate to get what she wants and your child turns into a willful spoiled amoral brat whose main attitude in life is "what's in it for me" and has no respect for herself, for her family, for God, for anything but Ronnie James Dio, Heavy Metal and the Soup? What if your partner was nothing but a sociopathic slob who never really gave a damn about the girl but used her to get back at you for whatever reason? How do you reach the girl before she goes out into the real world and they eat her up alive? Oh and the ex partner when confronted with how his daughter is (he has sporadically seen her throughout the years and thinks of himself as a "party dad" instead of a real father) and has told you that she is "your problem, not his" What would YOU do?