protected static function _getAllBalances()
    {
        $result = self::getClientInstance()->call('getprepaidbalancelist', array(
            "customer_id" => '0'
        ));
        $resellerSubAccount = (object)array('customer_id' => '0', 'prepaid_balance_amount' => '0.0000'); // 0 - is reseller's sub account
        array_unshift($result, $resellerSubAccount);
        return $result;
    }