I know this is going to sound worse than the spirit in which I offer it but... Step one might be to adjust the attitude from "Deal with these people" to something along the lines of "how might we best resolve the issue". No matter who you deal with, you will get much further with a good humble attitude rather than blame. It is my experience that if they list more than a very specific range of IP addresses on your network, you have a real problem. If you have a spammer at the top and bottom of a CIDR block then they may list the range, but I have had them lost two small ranges in the same /24 before... so I know they have very good specificity. I am sorry I can not offer you any specific steps or contact information to help you expedite the resolution, but I hope you will find some value in this advice. Perhaps, if your network is small and you control all your mail servers and you really are clean, you can configure thrm to relay through a smart host or SendGrid or etc. Good luck,Mike Sent from my Verizon Wireless 4G LTE smartphone -------- Original message -------- From: Bryan Tong <contact@nullivex.com> Date: 07/28/2015 8:06 PM (GMT-07:00) To: nanog@nanog.org Subject: Working with Spamhaus Hello All, SpamHaus has done us the favor of blacklisting all of our prefixes due to the issues with handful of IPs from customers we have removed from our network. They are now being unresponsive on helping us get these listings removed and we have a lot of legitimate customers who are no longer able to send email. If anyone has any advice on how to deal with these people. Please let me know here or off list. Thanks!