VM have recently updated My Virgin Media and you should be able to update the memorable word by logging in there.
When logged in click on Account Settings > Account Details > scroll down to Telephone Security Details (memorable word) > and then click on Edit
Which part do you think you are missing?
Hi staceymcfeeley1 👋
Thanks for posting and sorry to hear you're having some connection issues. I can see you've been able to contact us since posting, if you do still need help with this please let us know.