Spamhaus purportedly didn't answer even if it was aware because being a UK based entity it didn't recognize US jurisdiction.
I wonder if in US there is no way to send such kind of request with a legally valid medium including a non deniable return receipt. In other jurisdiction is mandatory to use such media for that purpose, and some acts may even be delivered by hand by a recognized state official.
Do Indiana still uses the Pony Express?
Biting the hand that feeds IT
