Where have you checked this?
Hotmail has his own blacklists.
If microsoft dont unblock your IP soon try to resend the unblockage formular again after one week.
http://miracare.mirapoint.com/checkip.html
i send form to hotmail,I have to wait a while and hope the problem is solved, maybe it was a coincidence that stop working when you install the dovecot-sieve and managesieved
