I'm fairly certain that if she still has the receipt for the gift card, she would be able to track down any purchases made with it. I had a co-worker get busted for using a gift card she found on the floor of the store we worked at during college. Those things have serial numbers that are activated upon purchase. If she legitimately sent the card and it was stolen along the way or Jay Bee is lying, it wouldn't take much effort to find out.
Who am I kidding? Of course she didn't send it. $50 is money that can go toward cheap garbage from Wal-Mart or food to stuff in her gut.