Cancellation of line

I have been trying to cancel my phone line for the last 3 months. Nobody responds to the online forms. I hold on for 35 minutes without getting through to someone and when I do I get cut off<br> <br> All I am trying to do is cancel my phone package and retain my ADSL line<br> <br> I am now writing to let you know that I will not be paying my phone bill until you call me back