Send an email to sympa@list.tuwien.ac.at with nothing in the subject line and in the message body put the following:

UNSUBSCRIBE LISTNAME EMAIL

where LISTNAME is the name of the list you wish to unsubscribe from (e.g. vsc, vsc-users, vsc2, vsc3, …) and EMAIL is an optional email address, useful if different from your From: address.