To solve your issue, you'll first need to log out from the game via the in-game settings. Make sure your account is linked before following this procedure:

• Open the game and go to the home screen.
• Click on the "Options" menu at the top right of the screen.
• Select the "Account Settings" tab
• Click on the "Logout" button and click on "Confirm"

After this, clear your cache:

[Android]

• Go to device setting > App > Guardian Tales
• Select Storage > Clear Cache > Clear Data
• Restart your device.
• Re-download the game.

[iOS]

• Hold the power button until "Slide to Power off" displays and turn it off.
• Hold the power button until your device opens again.
• Uninstall the game, clear your cache and re-download the game.