Have a problem with my primary account email has been changed, it's not mine

I have been having issues with services this week which hopefully seem to have been sorted. However during the process of contacting VM, it appears that the primary email address associated with my account has been changed and it now is not mine. I can do a lot by just putting in postcode and surname on the help page, but can't sign on to My Virgin Media on any devices other than my laptop. I can't change it or even reset password as the verification code goes to this weird address. Any ideas what I can do. Everything seemed to be OK until the 360 upgrade so don't know if something happened when it was done