I'm having pretty much the same problems as you. Friends who I thought for years were close friends have simply fallen out of my life. One of them reacted the same way as your friend when I confronted them pretty much blaming me for not putting an effort in the relationship and saying I was over reacting about the situation (I hadn't seen or heard from her in months after continuously reaching out). I'm coming to the conclusion that some people are just selfish and not worth it. In the past when I have reconnected with friends I realize why I hadn't been talking to them. Maybe you are just building this person up in your mind and they are really not worth the effort or worry. I KNOW it hurts to have long friendships like this fall apart, I'm going through the same thing