Subject: ISP, Black Hole Listed, Refusal to trace & block a spammer customer.
From: Abuse@ISP
Sender: Abuse@ISP

abuse@
Your domain added to a black hole spam list, as you refuse
to assist to eradicate your spammer customers eg by connection
logging &/or other analysis.  As more black hole lists add you,
your business may suffer. Your choice irresponsible.