Well this product is safe to sell, it is not a beta code, it doesnt require third party activation, people who bought graphic card like for minning they dont need the game so they can sell it in order to retrieve some money. And as any other code you shouldn’t qualify the seller before activating it. Steps are very clear and it can be done on phones too. Try reaching support and contact the seller in order to get replacement or something. Nvidia is granting a legal copy of games and its totally safe to link your account in order to claim a game. Theres few promotions like Battlefield V with RTX gpus, Monster Hunter : World, Counterattack set for Fortnite (most popular) etc etc .