How can I clear my iTunes balance to zero?

To clear your Apple ID balance, you will either have to buy something to zero your balance or contact Apple Support to zero your balance. If you have less balance credit than the cost of a single item, then contact Official Apple Support to zero it.

For more information ⇢ Change your Apple ID country or region - Apple Support

If you have less store credit than the cost of a single item, then contact Apple Support.

Important:

If you need to change your region, then click ▶︎ Change Region for step-by-step instructions. 🌐

Good luck! 👋🏼😉

Check How do I clear my Apple ID balance ? - Apple Community. There is some good info there.