Cancellation costs

Due to our telkom lines been ****** in our area and Telkom blatantly telling us that they will not be replacing the cables and that we have to go wireless, My MWEB ADSL account is completely handled by MWEB which includes the TELKOM ADSL line , so if your internet provider cannot provide you with the service you are paying for its their duty to either offer you a product that will be suitable or cancel the service. What MWEB decides to do is expect me to continue to pay for a service they cannot offer me and when i cancel they want me to pay for cancellation. I want answers as to how this is possible , i will take this further if i dont get answers .