Complex sentence: Initially she claims that she called because she wanted to know if Frank still intended to represent her, but when Frank pursues her, Rebecca taunts him with things she could have told his wife, or that perhaps she had given her advice on her sex life.
Split into simpler sentences: Initially she claims that she called because she wanted to know if Frank still intended to represent her. Rebecca then taunts him with certain things she could have told his wife, including advice on her sex life.