s6 new champions systems error

1/16 i play ranked game 2 time the time i quit the 1 time because our team couldn't got great champions but the 2 time i was lag in the pick and ban page and the game gives me note that i quit the game but i don't think my computer was lag at that moment and other things were keep working but this error make me lost 10 more lp and take 30 min for quit game. i feel bad about it.