Have you tried resetting the password for the account concerned within My Virgin Media? Sometimes the password servers at VM get out of sync.
Sign in to My Virgin Media, go to My Profile and/or Manage Accounts depending on whether the account concerned is your primary account or an additional one. Select the account concerned and then click on Change to the right of password if a primary account or View/Change then change to the right of password for secondary accounts.
_________________________________________________________ Graham I am a VM customer. There are no guarantees that my advice will work. To say thanks click the kudos thumb. If I have solved your problem please click the helpful answer button.