So... question... and possible troubling concern...

So, some year or two ago, I was given a $50 Visa gift card, and I wasted out the card. Then I just never touched it again until I found out that I could just use it as a way to get the free old-gen console games. Then, this year, I found out that I could
still use the card somehow, since it was applied as a payment option. Now, I got shook, cause the money should be drained, but if there's some money I have to pay up on a gift card, then I need to know so the IRS doesn't come knocking on my door.
Now, question, if the card is fully used up, and I need to pay it, if I don't pay the possible fee for the gift card, is Microsoft or a bank gonna terminate the card, or am I in for some possible trouble? I really
need to know so I can lay my worries aside. Cheers to anyone who can clear this up. (If it's anything, I terminated the payment option hoping the card can just fizzle itself out on it's own, but I need to know if it can still happen, or if I need to be worried.)

:)