Forced double w/o (rule 3.2.7.1).
Penalty per player: -1 point + -150 frags + 2 warnings (rule 2.2.6 + 6.2.2)
Penalties will be down-sized to 1 warning each if the game is rescheduled and played (rule 6.2.9).

You have to actually write when you are available (date and time preferably). "Hi, I am alive" or something like that doesn't count.
/Ceba