How do I delete an obsolete Virging email address?

I currently subscribe to Virgin Broadband, but long ago stopped using my Virginmedia email address, as checks revealed that it had been compromised in numerous past data breaches, and I was getting bombarded with spam and phishing emails.  I have previously requested that Virgin delete this still-active email address, but to date it is still live and receiving emails.  How do I get this email address deactivated?