Im lvl 2 too and +- 7 teams in my league are abandoned. There're even two abandoned teams (A & B) with less than 15 players got through playoff match and they played each other in qualifying match. A vs B 3-0, B vs A 3-0.

I think it's better when a season has ended, there should be a box that say "You have finished (number) during the last season . Go to the next season?" If the manager click "okay" to confirm then his team can go to the next level, or stay at his current level if he is not promoted. This should be done at the first day of the season. That way no abandoned team will make it to the next level by luck.

Just my 2c