RT_Any ideas for getting this redundant mail stopped?

["Brent" <brente@xxxxxxxxxxxx>]

Hi,

I've tried everything I can think of to stop the redundant mail from
realtraders.com short of unsubscribing including adding these addresses to
my block sender list all to no avail.  listmanager@xxxxxxxxxxxxxxx
realtraders@xxxxxxxxxxxxxxx and waltt3.thetrellis.net  I'm going to try
listserver@xxxxxxxxxxxxxxx next. Any suggestions?

Brent