I saw a post on one of the sites from the Colorado Attorney General warning that they are collecting without a license in Colorado. You may want to check and see if they are licensed in your state. Here are more links to their other phone numbers. They also call from 8773650025, 8778131682 and 8004932143.
http://800notes.com/Phone.aspx/1-877-365-0025/4
and
http://800notes.com/Phone.aspx/1-877-813-1682
and
http://callerr.com/8773831196
and
http://800notes.com/Phone.aspx/1-800-493-2143
and
http://whocallsme.com/Phone-Number.aspx/8773650025/6