Unable to download or update apps using my Apple Gift Card

I provided a gift card, thinking it would be an option for payment methods, but it did not work as I thought it would. I'd expected my apps to be able to update and download, but it was still asking me for my billing information. I then checked Apple support, and it said the current place I'm in requires either a credit/debit card or a gift card, which is fine, but it's not working at all.

[Re-Titled by Moderator]