Frankly? This sort of response above is unhinged. If this person is as awful as you say, just get them out of your life and move on. Trying to document everything, calling their friends and family, spending this much time on someone who is awful and not worth the time nor the effort? You’re going to drive yourself crazy and somehow they’re still going to be in your life making you miserable.
I’m sorry this person is terrible to you, but the best “vengeance” is forgetting all about them and being happy doing what you want to do. The more space they take up in your mind, the worse you’re going to feel about the whole situation.