Sorry to hear that you're having issues with your telephone line.
With our new landline via the broadband (VOIP or 21CV) extensions work in a different way to the way it would have worked with previous telephone socket connections.
If you wish to use extensions so that you can get service in your , this should be requested at the time of installation. We can the plug an adaptor into the nearest extension socket and then wire from the Hub to the adaptor.
If you do wish to still use your extensions, our Customer Care team can arrange a visit to get this set up with the adaptor and cabling. You can contact us on 150/03454541111 and they can get this arranged for you