If it is not a known issue you can also run tests on the phone line from that page and book an engineer visit to get it fixed.
Disclaimer - I don't work for Virgin Media. I'm just another VM user trying to help out so my answers may be wrong If my answer solves your problem please mark it as helpful as it may help others My setup: Vivid 200 Optical fibre with Hub 3 in modem mode connected to a Netgear R7000 router. Telewest/VM user since 2001.
As a Very Insightful Person, I'm here to share my knowledge. I don't work for Virgin Media.