"Dieser Internetanschluss ist zur Zeit nicht aktiv"

Hi,

I've just started a contract at o2. A technician was expected to come yesterday between 12-4pm to switch on my internet connection, but he did not show up.

I thought that he didn't need to tell me he was coming, so I installed my router still.
My router works fine; All lights are green (Wi-Fi, DSL, internet, info ...) but I don't have an access to internet. When I try to google something, a telekom page pops up and says "This internet connection is not active at the moment" .

Despite 7931863190 hours spent on the o2 hotline , no one seems to help.
I've seen on forums that it might be the technician (? the one I've never seen) who might have set up a wrong connection.

What can I do? Did someone experience a similar situation?
I'd love some help.

Thanks in advance,
G.