How do I find someone's unit?

I have a Marine ex boyfriend who has been harrassing and stalking me. Right now I am currently in AIT in virginia. But i'll be coming back home in december. I have a marine ex boyfriend who has been harrassing me and it is really scaring me and making me extremely uncomfortable. I am trying to find his unit so i can speak to his chain of comman about him. I have called the cops on him before but he drove away before they even got to my house. Because he was waiting outside my place the whole time and it's scary. He is texting me from different generated phome number. I have changed my phone number before. But he found out. He has texted me in over 100 different numbers. He has been doing this for over 5 months. I an extremely creeped out. Idk how to get away from him or what to do as of right now. I'm really grossed out on how he talks to me. I am in another relationship. I'm about to be engaged and he is VERY creepy. There is more text messeges but these are barely even half of it. It goes up to all the way up to November 2019. Our relationship was very toxic and mentally and emotionally abusive. He manipulated me and gaslighted me and made me feel less. He almost got me to committing suicide on multiple occasions. He drives me completely insane. I dont want anything to do with him and i have told him every possible thing so he can leave me alone. I feel like im in hell. I got ptsd from this relationship. That when i see him, or hear him, or he attempts to talk to me, i immedietly want to jump off a cliff or just rip my hair out. He does this thing inside of me. I cant explain it but the feeling sucks. I have been getting better. I've been healing and my friends have been helping me heal. There were nights where he held me hostage and would not let me go home and i'd have to physically fight him to stop touching me and to let me go