First, please try following steps:
- Launch Ending Days with available Google Play Games/Game Center/mogera.jp.
- Open "Menu" -> "Config" -> "Restore game user"
- Press your original ID and download it.
- After you confirm your UserID changed, close config screen and start game.
Please contact me from above "Inquiry" menu with following informations:
- Your current UserID
- Purchase order number (if exists)
- Error code (if you encounter)