I can't locate an official means of communication with you, so I'll post this here.
We signed up to CM last week, created our email and prepared our subscriber list. Then, came in today (Monday 1st) ready to dispatch a mail out at 10am. We are seeing a maintenance page stating the system won't be back until Tuesday 1am (in Melbourne Australia). While I can understand the need to undergo maintenance from time to time - did you send us any warning? Wiping out a business day this close to Christmas really isn't on.
an announcement was sent almost two weeks ago, but they've possibly forgotten about those that have signed up since.
But hopefully, the new CM will kick buttocks..