:/ I know the feeling. There have been some times where I've been in a match and my internet would go out, whether it was an issue with my Ethernet-over-powerline device or a service outage. Whenever these types of things happened, I would generally stop playing ranked for a while until I knew that my issues were resolved.
A few days ago, however, I found myself at 400 ping and I, for the life of me, could not understand what was causing it. After one more game at 400 ping, I figured this wasn't going away. So, I decided to get down to the issue. I created at least 10 custom games over the course of four hours to try to get to the issue, and I was finally able to determine that the issue was with my ethernet splitter. And so, I unplugged my ethernet cord from it and directly into my ethernet-over-powerline device. Ultimately, what I'm trying to get at is that LeaverBuster is supposed to be that encouragement for players to address any technical issues they may have as soon as possible. It's no fun to play in a 4v5, no matter what side you're on. LeaverBuster gives you a few freebies, but will ultimately slap ya if you get 'Bustered in too many games. If you ever have any further technical issues preventing you from playing in a game, I would recommend testing your stuff out in a custom game. If you're stumped, feel free to stop by the Help & Support stomping grounds and ask your question there! If anything, I'll be there to help you out to the best of my ability.
I'm sorry to hear that you've been LeaverBustered, and if there's anything I can do to work with you to resolve those technical issues, please let me know.