Get all customer orders in WooCommerce API

I am trying to get all orders that belongs to a specific customer using this endpoint in the WooCommerce API v2

http://woothemes.github.io/woocommerce-rest-api-docs/v2.html#view-customer-orders

using this library https://github.com/kloon/WooCommerce-REST-API-Client-Library

I have checked the website dashboard and there is pending orders

But I am always getting this response :-

[data] => Array ( ) [body] => [duration] => 1.36552 ) [response] => stdClass Object ( [body] => {"orders":[]} [code] => 200 [headers] => Array ( [Date] => Thu, 31 Mar 2016 07:37:35 GMT [Server] => Apache [X-Powered-By] => PHP/5.5.33 [Connection] => close [Transfer-Encoding] => chunked [Content-Type] => application/json; charset=UTF-8 ) ) ) )

Other endpoints in the API works fine this is my simple code

<?php

require_once( 'lib/woocommerce-api.php' );

$options = array(
    'debug'           => true,
    'return_as_array' => false,
    'validate_url'    => false,
    'timeout'         => 30,
    'ssl_verify'      => false,
);

try {

$client = new WC_API_Client( 'http://localhost/store', $API_KEY, $API_SECRET, $options );

print_r($client->customers->get_orders($userId));

} catch ( WC_API_Client_Exception $e ) {
    echo $e->getMessage() . PHP_EOL;
    echo $e->getCode() . PHP_EOL;

    if ( $e instanceof WC_API_Client_HTTP_Exception ) {
        print_r( $e->get_request() );
        print_r( $e->get_response() );
    }
}

?>