function _update_billing_ajax_action() {
            $this->_logger->entrance();

            $this->check_ajax_referer( 'update_billing' );

            if ( ! $this->is_user_admin() ) {
                // Only for admins.
                self::shoot_ajax_failure();
            }

            $billing = fs_request_get( 'billing' );

            $api    = $this->get_api_user_scope();
            $result = $api->call( '/billing.json', 'put', array_merge( $billing, array(
                'plugin_id' => $this->get_parent_id(),
            ) ) );

            if ( ! $this->is_api_result_entity( $result ) ) {
                self::shoot_ajax_failure();
            }

            // Purge cached billing.
            $this->get_api_user_scope()->purge_cache( 'billing.json' );

            self::shoot_ajax_success();
        }