Thanks for your post. I am sorry to hear of the phone line issues, and I do wish to help.
Is there any service faults listed on our status page here
Simply click the link, and then enter postcode only into the checker. Any known area faults will then be shown.
If none listed, then please sign in to the checker. To do this, you'll need your My Virgin Media online account details. When signed in, please click on 'run test' on the affected service; in this case the phoneline.
If this doesn't yield any results, can you unplug the phone line, wait two minutes, then replug it in, and try it for me? If that doesn't work, have you got another phone you can try? The benefit of trying this is to rule out the phone itself being the issue.