If you use an iOS device and you can't purchase Crystals due to the "Bank unavailable" error, make sure that there are no restrictions on making in-game purchases. In order to do this, go to your device Settings, find the "General" section, view restrictions, and make sure that “In-App Purchases” are enabled.
If you use an Android device, make sure that your Google account is listed in the Settings of your device in the "Accounts" section.
If your Google account is listed in the Settings of your device, and "In-App Purchases" is enabled, try restarting the game by removing it from the tray and launching it again. If you use an iOS device, double press the "Home" button, find the App in the tray, slide the App upwards and launch it again. If you are using an Android device, then this method may differ across different devices. Either tap on the home button twice, or hold down the physical "Home" button on the device itself to open the Recent Apps menu. Find the App from the list of running Apps, tap and hold the Application itself, and swipe it to the side to close it, and launch it again.
If this error persists try to do the following:
1. Close the game.
2. Log out of the AppStore (via the Settings menu of your device).
3. Launch the game, then return to the Bank and try to purchase Crystals. Enter your Apple ID profile data in the window that appears.
4. Confirm your purchase.
If you use an Android device, log out of your Google account, and log back in.
If you use an Android device, make sure that your Google account is listed in the Settings of your device in the "Accounts" section.
If your Google account is listed in the Settings of your device, and "In-App Purchases" is enabled, try restarting the game by removing it from the tray and launching it again. If you use an iOS device, double press the "Home" button, find the App in the tray, slide the App upwards and launch it again. If you are using an Android device, then this method may differ across different devices. Either tap on the home button twice, or hold down the physical "Home" button on the device itself to open the Recent Apps menu. Find the App from the list of running Apps, tap and hold the Application itself, and swipe it to the side to close it, and launch it again.
If this error persists try to do the following:
1. Close the game.
2. Log out of the AppStore (via the Settings menu of your device).
3. Launch the game, then return to the Bank and try to purchase Crystals. Enter your Apple ID profile data in the window that appears.
4. Confirm your purchase.
If you use an Android device, log out of your Google account, and log back in.