C&CZ can usually be reached on working days from 8.00 till 18.00 hour. Normally, the general helpdesk number will always be answered during these hours.
According to an international rule, every Internet-domain must have a "postmaster", who regularly reads mail addressed to him/her. You can ask this fictitious person any question related to mail. C&CZ uses this mail address also for all kinds of procedures, related to computer usage in the Faculty of Science, like requesting a new login, removing a login or changing disk quota.
The persons behind 56666 and postmaster change regularly.