Closure is something we use as a bullshit excuse to reach out or to go see someone. The only closure you need is that they are no longer in your life for whatever reason, no matter how much that hurts to hear.
Talking to someone after months in order to gain some sort of 'closure' will only bring you back to square one of the healing process. Why put yourself back in that hurt and start all over?
It's simple: DON'T. DO. IT.
No matter how hard it is.
Everyone can get in those moods where we just want to reach out to them. We all like to talk to and be around people we have comfort with. It's human nature, even if that person isn't in our lives any longer and/or shouldn't be.
When you feel like you want to attempt to start a conversation, but know it will go nowhere, remind yourself of these things.
If they wanted to talk to you, nothing could stop them. If you mattered to them, they would still be an active part of their life.
Remind yourself of the countless messages that have gone unanswered already. Think back, to what exactly happened. Think back to the times you silently cried about it, and they did nothing about it. Think back about the hurt and pain you went thru for days, weeks, and maybe even months afterward.
Remind yourself that you deserve more. That you deserve to be loved and respected in the same way that you gave to them so freely.
Have a friend or someone you trust that you can reach out to instead and just vent. If you don't feel comfortable doing that then write a letter, or more common in our generation, text it. Then next, delete it or throw it away. It gives you an opportunity to let it all out, without allowing someone to see you struggle.
Remember: Love yourself enough to know what you do and don't deserve.