Under Game Center in the apps, it shows I have a credit. But I can’t seem to use this credit for anything. What can I do?

I click on the App Store, it shows Game Center and my user name. Underneath, it shows I have a credit under $10.00 but I can’t seem to use it for anything. In my wallet section, it shows $0 balance. I’ve tried to log out and log back in- restart my phone and it still shows I have an unusable credit. Any ideas on how to resolve