waiting for team builder to find opposing ennemy team, then sudenly I have to agree to leave buster?

just waiting in the team builder matchup with my team forever, never knew I was the only one waiting in that queue, then apparently the game must have ended because I had to agree to a leave buster, so im probably going to get banned and once again its going to be (well this time more then) partially riot's fault

and I thought my teammates kicked me out or left the long waiting queue, had no sign of the game starting, pressed enter for messages and a message had popped never saw what was writing asked my teammates no answer, so I just went back to waiting