CodeIgniter maintain data through Controllers
You need to extend CI_Controller with your code and extend your classses from your custom class, not default. I'll try to explain:

At first create MY_Controller.php at /application/core/ with next content:

     &lt;?php

     class MY_Controller extends CI_Controller {
              function __construct() {
                      parent::__construct();
                          // Your checks here
              }
     }

     ?&gt;


Now edit your controllers like this:

was

class Support extends Ci_Controller {


will be

class Support extends MY_Controller {


Now your controller will use constructor from your MY_Controller and still use CodeIgniter's default controller class.

You can read more from the manual.