DSL with a fritzbox 7530, not working. Waiting for support from o2 for 3 months

Good afternoon,

I am very sorry for writting in english but I am new to Germany, and not yet confortable enough to have technical discussions in German.

I have signed a contract with o2 for DSL (o2 my Home M - 50 MBit/s Download and 10 MBit/s Upload).

The connection was activated 3 months ago, but I still have no wi-fi connection. My router is a fritzbox 7530.

The reason why I am writting here, is because I have called o2 more than 20 times and have tried all possible tipps received (which are usually two, update the router and check the cables), but to no avail. In the latest calls I was promised that I would receive a call back for booking another technical appointment, but no one called.

What do I have to do to book another appointment?? I have been paying for a product which does not work!

I hope that I can hear back from you through here, since any past attempts on the phone were not possible. If I still cannot book the second appointment, I will certainly cancel the contract and get my money back. In court, if need be, since you are breaching your side of the contract.

Best regards