The list of supported payment methods includes:

• iOS
• Android

If you've made purchases in the game or in other apps before:

• Verify if your internet connection is stable (a stable connection is required while making purchases)
• Temporary problems with the app store.  
• Problems with the store app. 

If you've never made purchases in the game or in other apps before:

• Check if the payment method you use is unsupported. It may be that the payment method you wish to use is not supported by the app store.

To fix payment issues:

• • iOS
  • Android