Why can’t I use my Apple id funds in my game

Have you had a payment method declined in the App Store or iTunes Store? If yes, see https://support.apple.com/en-us/HT203005

Also note that before you can add funds to your Apple ID, you must have a valid payment method on file. Learn about the payment methods that you can use with your Apple ID. See how to Add funds to your Apple ID https://support.apple.com/en-us/HT208687 Note that "after you authorize the payment, the funds ... [are credited] to your Apple ID. Then, you can use the credit to make purchases from the App Store or iTunes store. Need more help? Contact Apple support for help here: Get started

Also have you seen a message that says 'Your account has been disabled in the App Store and iTunes' https://support.apple.com/en-us/HT208856 If yes: "There might be a problem with the payment method that you have on file. ... When you see the message, don't try to edit any of your account information."

 You can get Apple telephone support for help in solving your problem using this link https://getsupport.apple.com/?caller=kbase&PGF=PGF63005&category_id=SC0245&symptom_id=23362 

You can also use this iTunes Support form https://support.apple.com/en-euro/itunes-contact. 

What happens when you try? Error message(s)? More information would help. If you see a Purchase couldn't be completed message, contact iTunes Support.

iTunes Store - Contact Us - Official Apple Support.