You might be better off sending in a support ticket through the account dashboard.

The answer from support is, "No, they will not provide a letter of exclusive use for an IP because if I destroy the droplet the IP is no longer exclusive use.". I understand this and explained how it is in my best interests to remove those IP's from my account with Microsoft's Junk Email Program if a were to the destroy the droplet in order to keep my own reputation from suffering due to the next owner of that IP. I fail to comprehend Digital Ocean's stance - if they say, "As of x/x/xx our customer so and so has exclusive use of this IP." - This is good enough for MS. How is this a problem? When they write the letter it is a true statement. If I destroy the droplet tomorrow it doesn't make it any less true than the day they provided the letter.

Oh well....I tried.

Can't you accomplish the same thing by registering with (Microsoft's) SenderID and, in addition, creating SPF records? See How to use an SPF Record to Prevent Spoofing & Improve E-mail Reliability.

Not to sound like I'm quick to stick up for D.O., but given that someone could simply destroy a droplet shortly after a Letter of Exclusive Use is issued, I'm surprised Microsoft would put so many 'eggs' in that 'basket.' While I see the argument that someone w/integrity would want to protect their reputation, it's not necessarily those people that Microsoft should be worried about.

It follows, then, that if a dirty, rotten spammer is willing to do a little dance to obtain a letter from an IAAS provider, only to destroy its approved cloud instances after obtaining a Letter of Exclusive Use, then how were Microsoft's e-mail customers protected from the big, bad spammer by that Letter of Exclusive Use?