Colin, I agree that Virgin media need to review their approach and train their staff better. Their cold-calling call-centre sales people sound very much like scammers and don't seem very clued up. They have no idea how to verify themselves as genuine Virgin employees, and sound very poorly trained.
Also I agree with your advice not to give security info to them. They made the call, they should be providing the security info to prove they are genuine and not scammers.
Don't think Richard Branson will have any view on their approach though, since Virgin Media has no connection to him!
Great that you're able to answer the question of who is calling. But can you let us know why this person has rang me 14 times in the last 5 days and hangs up whenever I pick up the phone? I've asked on 150 to be taken off any marketing subscriptions at least 3 times this year and I still get these calls, mostly trying to bully me into a contract I do not want. How can I simply get you guys to go away?
I have started to get calls from them AGAIN. Last time (May 2017) they confirmed that I had been removed from all marketing calls. This was the same message as the previous time (October 2016) and the time before that (February 2016). But the calls continue!