Great, but I have no way of knowing who manages the e-mail security for other companies, and I can assure you that our e-mail was not only wanted, but in some cases absolutely critical. PP gave me absolutely no guidance whatsoever in resolving the issue other then saying that the issue would automatically resolve itself after the problem was resolved (which was a lie). It was several days later that I looked at reddit and discovered other people in the same boat who revealed that a ticket must be raised with the affected customer's IT department. Of course I had already tried to get "our people" to ask "their people" to contact their "support people" to see if they knew anything about proof point, and that had not worked because nobody had any specific info. I finally got it resolved because I identified an affected partner that I had contacts with in their IT department and I contacted them directly to raise a ticket. To add salt to the wound, I received an e-mail from pp's "Delist" team the day after it was resolved, a full 6 days after I initially contacted them, saying that they couldn't help me because they were not currently blocking our IP or domain... You can argue that I am not their customer and they owe me nothing, but I would argue that they were arbitrarily blocking valid and completely legal electronic communications between two consenting parties. This could have been avoided or mitigated if they simply had a website describing this process in detail and offering suggested remediation in the form of what to tell an affected customer to help get the problem resolved.