Game connection bug

While I was playing a ranked game in my promos, in a team fight out of nowhere I got huge lag spikes when I was running on 100 fps and 60 ms. After some time my whole game crashed. I tested to see if it is the game or my internet but it was opening everything else. Now I try to play another match on normal and I have a 20 minutes leaver buster for 5 games, when league of legends crashed on me.