Birii, you are in an unfortunate situation. Due to region allocations, you will need to pay for this game via a Japanese method once the game becomes pay-to-play. This means either using a Japanese credit card or finding a method to get crysta on to your Japanese account.

The way the SE account system works, SE will be presuming you still live in Japan - we are unable to change our country of residence.

The only suggestion I can think of is to write an email to Square Enix Technical support outlining your circumstances. Who knows - they may be able to help you fix things up.

In the interim, welcome to the "I've been s****ed by the stupid billing system" club.