Not Receiving Newsletters in Hotmail Sent through ConstantContact

I am subscribed to a few mailing lists through an organization that uses Constant Contact to send mass emails. For the last year, I have not received any of them. The organization has checked their records to ensure that they have the correct email address. I have checked my junk folder, and the messages are never there. I have also checked my blocked sender list and added addresses to the safe sender list, to no avail. I would greatly appreciate it if someone could help me resolve this issue.