chiflon

It doesn’t work at all.
I’m having a lot of problems with this issue, please fix it!

it happens because the sorting it’s based on arrays
To sort on database data, you must to include in SQL query:

private function table_data()
  {
    global $wpdb;

    // Set defaults
    $orderby = 'razon';
    $order = 'asc';

    // If orderby is set, use this as the sort column
    if(!empty($_GET['orderby']))
    {
        $orderby = $_GET['orderby'];
    }

    // If order is set use this as the order
    if(!empty($_GET['order']))
    {
        $order = $_GET['order'];
    }
    $sql = "SELECT * FROM ".DB_TABLE." ORDER BY ".$orderby." $order";
    $data = $wpdb->get_results($sql, ARRAY_A);

    return $data;
  }

Replace line 363
$data = $this->example_data;
to
$data = $this->table_data();

Finnaly delete the usort_reorder() and usort functions.