We had one like this last week as well.  First you should probably check
to make sure that this is really the address this person is subscribed
under, by sending the following to listserv:
 
query vatican2 for *PHILLIPE*@attmail.*
 
If the address is really so convoluted, and listserv confirms that this
is the correct form, then you can uuse wild card characters to delete
him/her as well:
 
del vatican2 PW=YOURPASSWORD [log in to unmask]
 
And add the word "quiet" at the start of the command if you don't want
another error message.
 
This is a rather curious conglomeratio of characters that mail systems
operated by telephone companies seem to be prone to.  I had a student
last term who worked for Newfoundland Telephone, and his address was
very similar.  The only way I could write to him was if he wrote to me
first, so I had a reply line, and our mailer could find a gateway.
Seems somewhat ironic from companies whose primary business is
communication!
 
Bill