C&CZ can be reached on working days from 8.30 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.