Have you checked for faults in your area, you can login to your My Virgin Media and check your service status at the top right of the page or phone 0800 5610061 for a more localised check.
If there is nothing showing then you might need to call Virgin on 150 from a Virgin phone, mobile or landline, or 0345 454 1111 from any other phone to report a fault, then ignore all the options offered and you should then be placed into a queue to speak to someone.