When you call them back, with your Call ID information blocked, you get a recorded message that states that the survey you were called about is now closed; in two minutes?  The message also states that you can press a key on your phone to block further calls from them; sure!

I have been getting quite a few calls like this recently from various phone numbers.  If you call numbers back, remember blocking your Call ID information (*67 before the 1 + 10 digit number) only works on numbers that are NOT toll-free.  Toll-free numbers still get your Call ID information.