Push Notifications in ACS

I am new to nodejs and titanium. I am unable to see all subscribers in a channel using nodejs.

I have my summarized code as follows, but cannot proceed due to some errors. Need help.

var ACS = require("acs-node"); 
ACS.init(<app-key>');
ACS.PushNotifications.showChannels({
 name: 'myChannel' 
 }, function (e)
 { 
 if (e.success) 
 { 
     Ti.API.info("Android:" + e.devices.android_counts); 
     Ti.API.info("iOS:" + e.devices.ios_counts); 
 } 
 else
 { 
     console.log('Error:\n' + ( (e.error && e.message) || JSON.stringify(e)));
 } 
 });

When I am using this code I am getting an error "TypeError: Object has no method 'showChannels'. But in docs it is clearly mentioned that there is a function name showChannels.

http://docs.appcelerator.com/cloud/latest/#!/api/PushNotifications-method-channels_show

I even tried to call same APIs using rest APIs but got 40* errors.

Thank You.

Edit: My bad, it seems PushNotifications are not available through ACS, so I decided to call API through Rest and now problem seems to be different. I am getting "You are not authorized to perform this action" message. I tried it using curl as well as code, with session_id passed as parameter and without as well. I am unable to see see my channels subscribers count and getting same error.

curl -b cookies.txt -c cookies.txt -X GET --data-urlencode "name=chat" "https://api.cloud.appcelerator.com/v1/push_notification/channels/show.json?key=&pretty_json=true"

I called the same function after login trough curl only.