Don't fall for the privacy argument they make either. ("Well sir, the reason we don't know what card you are using is for your privacy protection.")
I usually reply, you bought the list of information I was on from a specific company. Probably a VISA, MC, or other issuing bank.
But sire, they just give us a number.
Are you doing this by paper? What's on your screen? Probably a call management program, that tracks who you call, answered or not, voice mail left, ........
Usually in the middle of that they hang up.
Hopefully I prevented the call from going to a few other people today.