Tomorrow my phone and internet line switches provider and I still did not get any new hardware. So it could very well mean, that I will be offline for a while. In that case, I wish everyone a Merry Christmas now!
To keep you updated:
My line has switched to the new provider, but the new hardware is still not here. Currently I cannot get through to the hotline to complain. Luckily I managed to get internet working with the splitter from my old provider and my router. But the phone does not work with it (probably because previously I had an ISDN line and I now switched back to an analog line, because I was using a analog phone anyway and one phone line and phone number is enough for me). To use the phone, I have to disconnect the splitter (i.e. internet) and plug the phone in directly.