Forwarded emails

Hi all, I use to have a email with virgin media when I left that service I lost the email access. I set up a hotmail email and set a forward on the virgin email so any important mail wasn't missed. The virginmedia email should have ended after a year. 3 years later I'm still getting forwarded emails however I cannot log on to virgin media to disablethis as I no longer have an account. It now seems the email has been hacked and someone is issuing fake mail and I keep on getting returned emails.
I have been on to my outlook account to try and block the forwarded emails using my old email address as the name to block but this hasn't worked. Can anyone help pls?