In a return letter, Acxiom responded “We are delighted to help understand our company, and the industry we serve better. Moreover, we are committed to increasing awareness in general," the company continued.

"For example, we recently updated our web site to answer common questions about our use of data. At the site, people can also enter their own questions and we'll answer those too."

Brian J. Dames, executive vice president of customer solutions for Harte-Hanks Direct Marketing, said that "Harte-Hanks does provide a variety of data services (such as address correction, change of address updates and analysis) to our clients, and in doing so we commonly act as a steward of information owned or licensed by our clients for marketing purposes," Dames said. "We are committed to operating in compliance with our legal obligations and using best-practices specific to consumer privacy and data protection for the information we support and the geographic locations we serve. We take care in how we craft contracts relating to consumer data, and implement controls designed to ensure privacy and data protection as information flows between our company, our clients and other third parties."

But some of the companies showed their shock and confusion on the reason that they are being included in this survey. A publishing firm, Meredith exclaimed that "We are a media and marketing company featuring magazines; digital platforms such as websites, tablets and mobile apps; local television stations; and custom marketing programs."

“We are not a large data broker like the other companies listed. We've asked Rep. Markey's office for an explanation but haven't heard back."

Some of the companies even had to think twice before giving an immediate response, pcmag added.