I would suggest that if you're determined to go down this route, then asking a lawyer is better than asking this forum.
You could do it yourself via the small claims process, but you'd need to bone up on what the basis of your claim is (eg the "reasonable skill and care" requirements of the Consumer Rights Act 2015), and what evidence you can present to show that VM should be held accountable.
In terms of a contact for either a summons, or the pre-action letter, just write to the company at their registered office (using recorded delivery).
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