Complex sentence: Bart refuses and tells her that he had nothing against her, Lisa and Maggie; his beef has always been with Homer and now that Bart is emancipated, he's free from his father's abuse.
Split into simpler sentences: Bart refuses and tells her that he had nothing against her, Lisa and Maggie. His problem has always been with Homer and now that Bart is emancipated, he's free from his father's abuse.