I think they only block /16 or maybe /24 blocks... Meaning they block entire ISP networks... What I do is to simply sign up to many cheap VPS until I get an IP that is not blocked... Then relay all e-mails via that server. I guess spammers have the same tactic, but it does work.
I've completely given up to try to get my personal mail server delisted, as I can't even get Microsoft to tell me why they blacklisted it in the first place.
Instead I'm nowadays just rejecting all incoming emails originating from Microsoft with a message telling the sender to use another non-Microsoft email account.
It's just stupid. I never had problems with any other mail provider, but trouble with Microsoft as long as I can think of.