Useless gift card costing me R1000

My mom sent me a gift card to buy shoes. Online it said Somerset mall had stock, but they said they don't have. When I try to buy online it refuses to pay and they tell me I can only use an e-gift card. Yet they tell me I can't use my gift card to get the e-gift voucher. They also cant return the gift card, so basically I am stuck with a useless gift card and my mom has a debt on her account for something useless!!! They fail to give me a solution as to how to proceed from here, if I can't get the shoes I want can they atleast reverse the gift card to my mom's account!