Game crash

I recently made a match and already had my champ selected. Every one in my team did as the game started it crash on the loading screen there wasn't anything. I could see my menu it says I was on a game but I couldn't join in it. Even after I quick the game and loaded back in the game just wouldn't start. It lead too me being afk and I got penalty for it after not being my fault. It happened again when I try joining another match I made it customs this time too test it out and after quitting the game 2 or 3 times it finally work. I got in but the ping was at 40 and % was not loading at all after 2 or 3 minutes I finally started loading. How can I fix this problem of the game crashing/or leaving me in the main page when I am done selecting a champ for a match.