I believe the problem you are having is that before you removed the
 user from the mailing lists, a lot of mail had already been sent.
 The "received mail from a served out user" messages are the mail
 rejection messages from the user's system.  They will stop when the
 system in question has bounced all the queued mail back to you.  If
 the mail system that is bouncing the mail had formatted the notes
 differently, then LISTSERV would have sent them to the list owners
 indicating that they were mail rejections.  As is is, the format
 isn't recognized as a mail bounce and they get trapped as "mail from
 a served out address" instead.  Either way, you were going to get
 them all, since they were queued for delivery before you deleted
 the address from your lists.
 
 -jj
 
 PS - I'm having the same problem here by the way.  He/She signed
 up to all JHUVM's lists as well.  It's been a royal pain. :)
 
 PPS - You could mail the postmaster at the ...east-anglis.ac.uk
 address listed in the mail header and ask him/her to purge the
 mail queued for this bonehead.  If they can do that (and if they
 are willig to), it would stop the flow at the source.