It is a real thing it shows Apple Account Balance is disable, it has nothing to do with Apple account being disabled.
apple account balance is the credits from apple store credit or you redeemed a gift card or your refilled more cash to your apple account .
the issue happens randomly for no reason and no one in apple knows how to deal with it. I have the same issue.
it happens when you use your apple account balance shop on Apple online store, then the order canceled. Apple immediately lock your “Apple account balance” rendering your account un-useable. Like a bad break up!
the reason why it will make your entire account unusable is apple’s stupid system force to use apple account balance off first if it sees you have balance in your account before switching to other payment method. Even when the balance is disable by apple.
to make things worse no one know why apple will disable a gift card/store credit balance. Personally, when you call 1-800-my-apple people there are equally clueless I been transferred from the front line agents to apple tier 2 support level, and to different departments: apple care department, sells department, billing department, post sells department, tech support, apple media services, iTunes department, apple gift card department.
no one know how to solve the issue !