DSL Internet contract termination

Sorry for asking in English due to my poor Deutsch.

To summary, I have no Internet access but I'm charged on monthly pay for the Internet and my request for the termination is rejected from O2.

2 weeks after I applied for the Internet, which is able to terminate the contract monthly, the technician came to my house and installed the Internet. He said, "30 min later after his leaving Internet will be activated". But I was not able to access the Internet. 1 week later, the technician came again. He checked the Internet and said, "Internet hurb(Leitung) at your home is out of order, so you need to call an electrician and fix it." Afterwards, an electrician from my apartment came to my house and check the Internet and said "Internet is all OK at your home, the Internet technician might be confused to find the right Leitung because there are two Leitung in your apartment but only one is for your room." And I called the technician but real problem began. The technician canceled the appointment three times in a row for 2 weeks. I was waiting at home at the day and I got a call the appointment is canceled. I got too much stress because I came home early and waited with coming out of my school early. Afterwards, I decided to terminate the contract and I sent the letter to O2. But O2 rejected my request for termination because the Internet is fundamental thing in house, so it is not possible that there is no Internet your home.(actually I don't understand and accept the reason.) Anyway, I don't need to Internet anymore in my current house because I'm moving to another city from October and the internet is included in my new house.

But I don't know what should I do in this terrible situation....
I'm not able to access to the internet but I'm still charged on the monthly pay and technician doesn't come to my house but my request for termination is rejected....

What should I do??