For me it looks like, that the domain ‘bluewein.ch’ is not in control of Swisscom, but it is in control of the person who most likely also controls ‘ict-olten.ch’ and ‘cuida.ch’.

You could try to contact Datawire AG, as the IP address of the ‘mailserver’ ‘mail.ict-olten.ch’ is hosted by them… maybe prepare a message and ask them friendly to forward it to their customer. That would be my approach.