It is a scam, those have been around awhile. You fill out a long survey and give them your name address, phone number, email address, and they give all theme to the spammers, then there are a lot of offers for credit cards, etc. you usually have to sign up for 3 or 4 of the offers and use them a while before you get the gift card. Since you have provided them with all the info, and the spammers who subscribe to their service do not have to honor the do not call lists, etc. on the basis they have had previous contact with you. if you read the site, or possibly in the call it will have buried in it someplace "participation required".
"The Constitution is not an instrument for the government
to restrain the people, it is an instrument for the people to restrain the
government lest it come to dominate our lives and interests." Patrick Henry