Problems with step-mother

My parents were separated when I was two and divorced when I was 10. Now I live with my father and his 2nd wife. Relationship between her and me is not stable since her entry in the house. She always says something objectionable about me to father and father doesn't investigates. She ruined my character in front of him and my neighbours. Every time hates me. Does anything to distract me from studies, and I am preparing for medical. But she always disturbs me. What shall I do? I complain to father. She puts the blame on me. Anyhow..! What is the solution..? I am not able to tolerate these things anymore.