To make in-game purchases, you need to connect your account via Google Play Games settings.

Also, check that you have a reliable Internet connection.

Check your balance and connected payment methods in Google Play Store settings.

Find more information about answers to all your questions here:

https://support.google.com/googleplay/answer/1050566

https://support.google.com/googleplay/answer/1267137 

 

If these tips didn't help, please get in touch with our technical support team, and we'll be sure to help you.