OK, I finally got very curious and called the telephone number in
the original spam.  It's a voice mailbox which says, in about so many
words, (I don't remember the specifics...)
"Hi, this is [name].  All the items which I advertised for sale on
the internet have been sold.  If you're calling to complain about my
use of the internet, feel free to leave a message, or call Netcom
at [number] if it will make you feel any better."
is Netcom somehow involved in this??
 
Nate