Gift cards are like cash and are fully controlled by the person or company in possession of the card number.
Because of this cash-like nature, there is no mechanism to 'dispute' or 'charge back' a purchase made with a gift card.
For Visa or Mastercard gift cards:
Please contact the merchant where the purchase was made to resolve any purchase issues or request a refund.
For store-specific merchant gift cards:
Contact the merchant's gift card support online or by telephone.