Not much here to answer. Were you injured by the claims? Was it a political ad? Was it opinion? Was it protected by free speech? Was it "mere puffery?" Take the details to an attorney, and show in dollars or reputation, how much you were injured.
We do not have a client/attorney relationship until you make an appointment, we discuss your case face to face, I accept a retainer, and we explictly agree to enter into representation.