I get calls all the time at work and they usually go something like this.

Caller: Are you the person in charge of making purchase decisions for I.T. at your company?

or

Caller: We are a fortune company stats collector and would like to update our records and they usually have our address etc and than have the name of the people who hasnt worked with us for 8 years.

My answer the above:  "Sorry I am not obligated to provide that info"

and that ends the conversation right there.