Sharing Our Innermost Thoughts

My ex best friend used to laugh with people who would call me a sl*t for having kissed my boyfriend once and used to say that she will never be able to achieve her career goal because she’s a girl.
He started asking me to break up with my boyfriend of 2 years because according to him, my boyfriend didn’t treat me right. He then stopped talking to me because I wouldn’t break up. My friends and I thought maybe he’s going through something so we should reach out to him and let him know that we’re here for him. He simply humiliated us on that call so we left him alone.
Later, I got to know that he has told people that he likes me. Then he tried to hack into my gmail account and when I confronted him about about the same, he started yelling at me and threatening to tell my parents about my secrets. When my other 2 friends joined that call, he said he didn’t try to get into my account and he was just trying to reach me. (I hadn’t blocked him anywhere lol). We then decided that we’re done with his drama and aren’t going to talk to him. After 2 months of that decision, he tried to reach out to us again and he didn’t accept his fault. Instead he completely ignored when I said that he hurt me. Later he tried to hack into my Instagram account and when confronted, he said he didn’t do it and even if he did, I can’t prove it. Then his brother threatened us three that he has connections and all. We came to a conclusion that this person shouldn’t try to contact any one of us and now the chapter is closed.
I did a mistake because I really wasn’t okay. I used to have anxiety attack literally everyday. A friendship of 5 years, ending just like that. I needed answers to why he treated me like this so I reached out to him and asked him to explain so I can get my closure and move on. He said that I should find my closure on my own and he doesn’t care about the trauma and anxiety attacks he caused me. Now, everyday I question where did things go wrong. I can’t explain it to my friends because they don’t really wanna talk about this whole episode since it was a bad experience for all of us. I don’t know how to feel better when someone so close to me used to actually make fun of me with his friends and then he did all this.