We're sorry to hear that. To prevent this from happening in the future, be sure to set a password prompt to appear before any purchase is made.
On Android
1. Open Google Play and tap the Menu button in the top left.
2. Press Settings at the bottom. Under User Controls, select Require Authentication for Purchase.
3. Select For all Purchases through Google Play on this device.
On iOS:
1. Quit the game and go to your iOS Settings menu.
2. Choose iTunes & App Store, then Password Settings. Beware that this option is only available if you're not using Touch ID to confirm your purchases.
3. Tap the Always Require line. After you confirm this option with your password, all further purchases will require for the password to be reentered before they are completed.
On Android
1. Open Google Play and tap the Menu button in the top left.
2. Press Settings at the bottom. Under User Controls, select Require Authentication for Purchase.
3. Select For all Purchases through Google Play on this device.
On iOS:
1. Quit the game and go to your iOS Settings menu.
2. Choose iTunes & App Store, then Password Settings. Beware that this option is only available if you're not using Touch ID to confirm your purchases.
3. Tap the Always Require line. After you confirm this option with your password, all further purchases will require for the password to be reentered before they are completed.