I just called the number and found it was ComNet. I guess it was from my public radio or TV station.
http://www.comnetmarketing.com/
From the website:
ComNet Marketing Group is one of the nation’s most respected providers of marketing and professional fundraising services to the non-profit community. Our comprehensive approach integrating telemarketing and direct mail is used by many of America’s best known member-driven non-profit organizations:
* Public Television
* Public Radio
* Professional and Trade Associations
* Museums - Science Centers
* Zoos and Aquariums
* Conservation Groups
* Health Advocacy Organizations
* Performing Arts Organizations