Unable to purchase
I want to empty my apple ID balance so that I can buy other apps and data in my country.
Question marked as
If you need to zero out your balance
You have 2 options
Have at least 1 other valid payment method and make 1 purchase or more purchase until you zero it out.
For the last purchase costing less than the cost of what you are buying some of it will be taken from your Apple ID balance, the rest from the payment method.
Or you can ask apple to remove it after buying something until you have less than the cost of a single item
Contact Apple for support and service - Apple Support
From:
Change your Apple ID country or region - Apple Support
Contact Apple Support
If you can't complete any of the steps, can't change your country or region, or you have less store credit than the cost of a single item, contact Apple Support.
Good luck!