Cannot login with my (now non-existent) email name

Hello: when I first created my Virgin Media account (the master one for my package) decades ago I used my then-current email address which no longer exists.

I wish to manage my account - view bills, view packages and the like - but am now (14 July) confronted with a demand to verify my email address at the login page by responding to an email sent to that (defunct) address.

Of course I can't t do this since the email address does not exist - the verification link can't be sent to an email which doesn't exist!

How can I have my email login name changed to a current (working) email address?