Loading Screen AFK

I left a game and got leaver buster. I understand this was my fault, and that leaving a match cannot be tolerated. So, I completed 5 games on low priority queue, and after 3 days, started a normal queue game. Everything began to load normally, until everyone was at 100%, except for one guy who was not connected yet. I waited for 7-10 minutes, and nothing happened. So I grew suspicious of what happened, and alt tabbed to see my internet. It was perfectly fine, so I waited a bit more. Then my game crashes, I reconnect and the game has been running for 10-15 minutes. Afterwords I was put on leaver buster again. My internet was fine throughout and didn't malphuntion. I can't really give much more detail, but I hope this gets looked at :(