Virgin Media clearly don't want to support the email service. It's no longer possible to create new mailboxes and email is not available at all to new customers. All of my family have had virginmedia / ntlworld email addresses for years but I moved them to gmail when VirginMedia went down a few weeks ago.
Virgin Media have declined rapidly. I've been with them (and the predecessors) for decades and the infrastructure was virtually 100% reliable. In the last year, everything seems to have fallen apart. The Broadband is unreliable and doesn't meet the advertised speeds, TV is often pixelated and I was without a landline for 7 weeks earlier this year. I had to take them to Ofcom to get compensation and even then they didn't pay up until I started legal proceedings. I just hope that BT or one of the other fibre companies is available by the time my current contract is up.