Target review: target gift card

My nephew and his wife registered with Targets baby registry on our suggestion. We gave them a $75 Target gift card. My nephew and his wife were informed the balance on the gift card was $0 by the cashier at Target store in Goodyear AZ while trying to purchase a car-seat on black Friday, 11/23/18. They then checked the balance on Target.com, in which it indicated $0. The Card went directly from my wife's sole possession to our nephew who scratched off the code in the back to use it. We paid $75 cash for this Target gift card on 11/18/18. We have a receipt. We assumed the gift card was just not activated correctly by the cashier. We would like a refund for our purchase. Targets guest services did not seem to care too much on resolving our situation. Could not tell us much on the gift card even though we provided them with the receipt and gift card number. We would like to get our $75 dollars refunded. We feel we donated $75 to Target or Target just took our money. Please help us resolve this situation.