HELP! cocos2d-x & Google Play In-app purchase

Hi There,

I integrated the Google IAP with cocos2d-x. It often works well and could add coins to users’ account, but sometimes not, Are there anything wrong with my code? Thanks

public void onConsumeFinished(final Purchase purchase, IabResult result) {
mActivity.runOnGLThread(new Runnable() {

        @Override
        public void run() {
                Log.i("sku:", purchase.getSku());
               // in cocos2d-x context, add coins to user account
        }
    });

}