Cable internet activated but not working

Hi,

I am growing extremely frustrated as cable in my apartment is supposed to be working since 23rd of August but the light of Fritzbox6600 keeps blinking and there is no internet. No technician showed up to install the line (despite the hefty price I paid for installation). Then you sent me another modem but still not working. Then you told me it is a vodafone problem since you rent the line from them in my apartment and gave me a number to contact them. I am tired of calling people all over Berlin with nobody able to help. I signed up a contract with o2 not Vodafone so I need this problem to be sorted out by you.

Do something!