Resetting account balance on Apple Account

If you are in a region that does not have Apple Support, then you only have 2 options:

• Add a payment method for your current region and make a purchase. Any amount will first be deducted from your Account Balance with the remainder charged to your billing method.
• Abandon your Apple Account completely and create a new one. I suspect you are changing regions, so it may be necessary to change your phone number to use with your new Apple Account. This will result in the loss of data from your previous iCloud account.

You would have to contact Apple directly:

Contact Apple Support - Apple Support