To use my gas card, I pay at the pump that isn't gas card just like I would any other credit visa card.
If my drink costs above the balance on my card, the cashier informs me that my gift card balance is zero and asks me how i would like to pay for the remaining debt. https://Groups.Google.com/g/giftcard-mall-my-gift-info/c/lJb4jNQqwjY