How do I fix this?

I Uploaded a Visa gift card to my App Store and the funds recently ran out and the App Store keeps saying that I need to update my billing information When I try to download a free app or update app as that I already have. So I tried to update it with a new card and the same previous card That was used and nothing is working. I can’t download or update any apps. Help!

I have an IPhone 6 with IOS 12