Some information related to Microsoft blacklisting:
https://technet.microsoft.com/en-us/library/dn458545%28v=exchg.150%29.aspx
https://mail.live.com/mail/services.aspx
A form to declare valid IP from your domain:
Look at your logs
Look at the message in your mail log. You should see the email address of a contact. You can also directly send an email to delist@messaging.microsoft.com
Check with a tool
A good tool to check if you are blacklisted: http://mxtoolbox.com/blacklists.aspx
Check you DNS zone file
Once blacklisted, make sure you are correctly setup on your side and check your DNS zone file: – SPF record – PTR
Send an email to gmail.com or yahoo and check the email header, it contains details regarding SPAM detection and SPF check.