Seven days for 20 turn battles mean an average rythm of 3 turns/ day, which some players seem to have difficulty to keep.
I've found myself with 2 games unfinished, and I was unable myself to end properly a match because I had to go out of city for 3 days in a meagre summer holiday

It's not a complaint about any player, I understand perfectly that people have RL duties and that and this is, after all, just a game.
But I would humbly suggest to tournament directors to consider making the time spans a little longer.