i'd change from US to TH store
please help i'd change from US to TH store, error "You have store credit balance you must spend you balance before you can change store."
iPhone 6, iOS 8.3
See the quote below from Can't change the country of your iTunes Store, App Store, iBooks Store, or Mac App Store account - Apple Support
Store credit balance
You must spend your balance before you can change stores.
If your store credit is less than the cost of a single item on the iTunes Store, App Store, iBooks Store, or Mac App Store, you can add a credit card to your account. When you buy an item, you will use the remaining store credit and charge the remainder of the purchase to your credit card.
If you don't have a credit card, contact iTunes Store support.