You are correct to assume this "green screen of death" means your box has failed.
VM forum staff respond on here, but their current response varies anything upto a week. You can try the text message service (07533 051809) but I'd strongly recommend you persist with the call queues as the quickest way of getting this resolved.
Sometimes the automated service tries to "help" you by fixing some issues remotely, it then forces you to redial 10minutes or so later when those fixes have failed..
I'm a Very Insightful Person, I'm here to share knowledge, I don't work for Virgin Media. Learn more
Have I helped? Click Mark as Helpful Answer or use Kudos to say thanks