Update: I managed to contact the customer service using the live-chat and they opened a ticket for my problem. An appointment with the technician was issued for today and although he didn’t physically come the issue was resolved. 

Hello @mrcs, welcome to our o2 community and thank you for your feedback :-)

I am glad to hear that this issue could already be solbved. Not in every case it is necessary that a technician appears directly in your flat, very often things can be fixed remote, always depending on the cause of thie issue.

If there are still questions open feel free to ask, we will answer as soon as possible :-)

regards,

Lars