Have you changed your settings to not accept private messages from Kate? That might be why you aren't receiving the messages about being entered in the DT lotto.
You aren't missing much, the disappointment I get every time I wake up to 2 messages from Kate and both saying :
You ranked among the 150 top players in one of today's tournaments.
You will therefore be entered in the Collector Lottery!
Unfortunately you didn't win any Collector characters this time round.
You'll get your message at the end of the day. The lottery happens per day, not per match. There are 5 Crs distributed to the 12 x 150 = 1800 players.
Also remeber that getting top 150 in Standard does not alwas equal top 1/3rd