How to reset Apple ID balance?

Buy something more expensive than your balance and use a different payment method for the excess amount; if you can't, ask the iTunes Store staff to zero it.

If you're referring to a different store, check its documentation.

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Contact iTunes Support for assistance. See the Apple Support articles below for contact information.   

iTunes Support – world wide   -

Apple Support schedule phone call     -

Billings and Subscriptions   -

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