Add Contact to Constant Contact Using cURL

ConstantContact.php

<?php
  //Not original code, just don't want to loose it
  // fill in your Constant Contact login and API key
  $ccuser = get_theme_mod( 'ccuser' );
  $ccpass = get_theme_mod( 'ccpass' );
  $cckey  = get_theme_mod( 'key' );
  
  // fill in these values 
  $firstName  = "";
  $lastName   = "";
  $emailAddr  = "email@email.com";
  $zip        = "";
  
  // represents the contact list identification number(s)
  $contactListId = 1;
  $contactListId = (!is_array($contactListId)) ? array($contactListId) : $contactListId;
  
  $post = new SimpleXMLElement('<entry></entry>');
  $post->addAttribute('xmlns', 'http://www.w3.org/2005/Atom');
  
  $title = $post->addChild('title', "");
  $title->addAttribute('type', 'text');
  
  $post->addChild('updated', date('c'));
  $post->addChild('author', "");
  $post->addChild('id', 'data:,none');
  
  $summary = $post->addChild('summary', 'Contact');
  $summary->addAttribute('type', 'text');
  
  $content = $post->addChild('content');
  $content->addAttribute('type', 'application/vnd.ctct+xml');
  
  $contact = $content->addChild('Contact');
  $contact->addAttribute('xmlns', 'http://ws.constantcontact.com/ns/1.0/');
  
  $contact->addChild('EmailAddress', $emailAddr);
  $contact->addChild('FirstName', $firstName);
  $contact->addChild('LastName', $lastName);
  $contact->addChild('PostalCode', $zip);
  $contact->addChild('OptInSource', 'ACTION_BY_CUSTOMER');
  
  $contactlists = $contact->addChild('ContactLists');
  
  // loop through each of the defined contact lists
  foreach($contactListId AS $listId) {
      $contactlist = $contactlists->addChild('ContactList');
      $contactlist->addAttribute('id', 'http://api.constantcontact.com/ws/customers/' . $ccuser . '/lists/' . $listId);
  }
  
  $posturl = "https://api.constantcontact.com/ws/customers/{$ccuser}/contacts";
  $authstr = $cckey . '%' . $ccuser . ':' . $ccpass;
  
  $ch = curl_init();
  
  curl_setopt($ch, CURLOPT_URL, $posturl);
  curl_setopt($ch, CURLOPT_HTTPAUTH, CURLAUTH_BASIC);
  curl_setopt($ch, CURLOPT_USERPWD, $authstr);
  curl_setopt($ch, CURLOPT_POST, 1);
  curl_setopt($ch, CURLOPT_POSTFIELDS, $post->asXML());
  curl_setopt($ch, CURLOPT_HTTPHEADER, array("Content-Type:application/atom+xml"));
  curl_setopt($ch, CURLOPT_HEADER, false); // Do not return headers
  curl_setopt($ch, CURLOPT_RETURNTRANSFER, 0); // If you set this to 0, it will take you to a page with the http response
  
  $result = curl_exec($ch);
  
  curl_close($ch);