>> Make it a legal and business decision instead of a technical one.
I'd go further and say that choosing to unblock some IP addresses out of a block you don't like is always going to be a business decision. The whole rationale for blocking in the first place was that a sender is untrustworthy.
Untrustworthy senders generally don't have a team of lawyers, and if they do (and they're actually sending spam) you can show what spam they sent and keep them blocked.
All the legal letter does is force someone who's otherwise too busy to look at this particular case for the 5 seconds it takes to determine that it's not a threat. Sad to say that being head of IT for a company for a decade doesn't get you the same level of respect; it might if they even bothered to open your email, but there's something about postal and legal letterhead.
I'd go further and say that choosing to unblock some IP addresses out of a block you don't like is always going to be a business decision. The whole rationale for blocking in the first place was that a sender is untrustworthy.
Untrustworthy senders generally don't have a team of lawyers, and if they do (and they're actually sending spam) you can show what spam they sent and keep them blocked.
All the legal letter does is force someone who's otherwise too busy to look at this particular case for the 5 seconds it takes to determine that it's not a threat. Sad to say that being head of IT for a company for a decade doesn't get you the same level of respect; it might if they even bothered to open your email, but there's something about postal and legal letterhead.