It has taken a very long time, but finally, I have cable TV and internet in my flat! The technicians came today at 7:15 am, the worked for almost an hour, and then everything was done, and I could just plug in the RJ-45 cable into my notebook, switch on DHCP, and be online. Same with TV: I only had to start the automatic channel search, and after a minute, I had all 36 TV stations available.
Later, I have to do some performance tests, how fast everything really is, whether i really got my 4 mbit down/1 mbit up. And I can finally move my servers from my old place to the new flat.