My girlfriend is repeating bullshit that my ex boyfriend is telling her back to me, what should I do?

My girlfriend and my ex boyfriend work at the same High School as teachers.

My ex boyfriend recently told my girlfriend that he has the power to destroy my future career as a teacher.

My girlfriend repeats everything my ex boyfriend tells her, even his BS.

What do you think of my girlfriend? What should I do about her?

My BF left me just before last years valentines day but i got this http://getboyfriendback.lovez.it and we have been almost a year together and are happier than ever.