How to empty my Apple Store credit?

Contact Apple Support directly, they will help you clear your balance, click -> Get Support

Fill in the field >Tell us what's going on<

If you then want to change Country or Region, you must comply with all regulations described here -> Change your Apple ID country or region ->  Change your Apple ID country or region - Apple Support (KW)

—First—

Make a request to zero out any remaining balance on your account by contacting Customer Support by phone or chat:

• Chat now or call 1-800-APLCARE.
• International Support.

—Next—

Cancel your subscriptions and wait until the end of the subscription period. 

—Then—

Click ▶︎ Change Region. 🌐