Rav3n420

This has nothing to do with the topic. But i need serious help. I can't seem to be able to find my roommates server. I've searching for him in every server mode but his name never shows up. And every time he invites me, eventually I'll get disconnected from his server. Not to mention we have some serious glitching whenever we try to explore caves. What can be done about this? I've sent them a forum, but we don't know the server number and can't seem to find it either.