Deleting virgin.net email account

I have a virgin.net email account which I ceased to use a long time ago, probably decades ago. I set up email forwarding on it then and occasionally get email forwarded from it so I know it is still active. In the last few months the forwarding has been passing on lots of spam email. I cannot however find a way of accessing it via webmail to block the spam or to close the account. When I try to access it via Virgin Media email it does not recognise the email address or password and will not let me reset the password (which I think I have probably got right anyway). In short, I would like to access this account to set up stronger spam blocking or would be just as happy to now delete the account. Can a Virgin Media customer advisor help me to do this please? I do have a Virgin Media broadband account. Thanks.