All in-app purchases in War Robots are processed via Google through Google Play Store. To see a list of the purchases, view your Google account purchase history:
- Go to http://payments.google.com/ and log in with your Google account;
- Select 'Activity' on the left;
- Choose an entry to view a receipt.
Read more about more ways to view your order history: https://support.google.com/googleplay/answer/2850369?hl=en