AITA for speaking to a girls ex and then asking her what her problem is with me? (context below)

basically she was in an old friend group of my exes, who was really abusive towards me and manipulative to everyone around him. yes, sometimes i would hit back. sue me. anyways, she’s had this thing against me ever since i replied to her ex flirting w him as he was w me,
me and the girl were never friends btw. she just talked bad about me behind my back constantly. i was lonely n wanted a smoke buddy or something, fast forward he was tryna sleep w me bc the girl told him to sleep with a bunch of “fat bitches” lol, which obvs upset me. anyways, the other day she got involved again so i asked her what her problem with me is, and in turn she just plain made fun of me for it all saying i think im so sick for what i did and that i did it to get to her when it was nothing about her. her and her best friend then proceeded to send a video of them saying “no one wants youuuuuu” and i genuinely didn’t even know what to do cos i didn’t wanna make it worse either. AITA?