How do I get my old address canceled?

I've tried about every trick I can think of to get this mail server to
stop sending E-mail to my old address, frwillia@.... That one is
still being forwarded, but gives me two copies of this lists rather
voluminous output. I am receiving the list on my new E-mail address,
that is working.

Any ideas? Is there a place I can write when the bot doesn't seem to
work?

Thanks
Fitch