" In addition to Form 8822, Change of Address, you may be able to update your address via phone, through a written statement, or on your tax return. You can see the IRS’ most up-to-date address change info on the IRS website."
" If you live overseas and haven’t filed taxes in a while, you still may still be eligible for a stimulus payment. However, if you haven’t filed your 2019 return, you will need to claim the payment as a refundable tax credit when you file your 2020 return. For full details, visit the IRS’s website."
IRS Economic Impact Payment line at 800-919-9835, 1-800-829-1040 전화로 문의를 해보시는게 좋을 듯하네요.