Internet not working. DSL light blinking

Hi.

I desperately need some help in english. I have a problem with o2 dsl since this morning. The yellow dsl light is blinking on the router and subsequently there is no internet.

I called the helpline and after 30 mins of waiting i got to talk to the guy. He spoke no english but i tried to talk with the german knowledge i have.

He tested that the router is not faulty and the problem is not from o2.

He says that maybe the problem is from the Keller(attic). I dont know how common this is. A wired connection doesnt just break automatically over night. So i am just a little indifferent with this diagnosis. Can anyone who had a similar problem share their experience.

I am expecting a call back in 48 hours from the people at o2.

Any help will be much appreciated