Problem with PHP class for MySQLi Request - php

Question

i've some trouble with my Script.
I'm trying to create a login script based on classes
The mysql request is handled by the checkLogin Class.
If the request is succesfull it return the Result to the login Class (throw back to index.php with ?status=1)
My Problem is that the SQL request isn't triggered and throws back with ?status=0
I've testet the SQL in phpmyadmin and its correct.
I've testet the $this->postUser and it contains the correct value
<?php
require ("globals.php");
require ("../src/class.connect.php");
require ("../src/class.login.php");
if($_POST)
{
if(isset($_POST['submit']))
{
if(empty($_POST['user']))
{
$request = null;
}
else
{
$request = $_POST['user'];
}
$a = new login($request);
}
}
?>
--class.connect.php
<?php
class dbh
{
private $servername;
private $username;
private $Password;
private $dbname;
protected function connect()
{
$this->servername = HOST;
$this->username = USER;
$this->password = PW;
$this->dbname = DB;
$db = new mysqli($this->servername, $this->username, $this->password, $this->dbname);
mysqli_set_charset($db, 'utf8');
return $db;
}
}
?>
--class.login.php
<?php
class checkLogin extends dbh
{
private $postUser;
protected function getlogin()
{
$this->postUser = $this->request;
$SQL = "SELECT user, isadmin, user_data, name, surname FROM `fm_user`, `fm_support` WHERE sup_id = user_data AND user = ? LIMIT 1";
$stmt = $this->connect()->prepare($SQL);
$stmt->bind_param("s", $this->postUser);
if ($stmt->execute()) {
$result = $stmt->get_result();
$getUser = $result->fetch_assoc();
$result[] = $getUser;
return $result;
}
else
{
header('location: ../index.php?status=0-'.$this->postUser); //$this->postUser - Just to check if the Value is correct given.
die();
}
}
}
class login extends checkLogin
{
protected $request;
public function __construct($request)
{
$this->request = $request;
$this->showLogin();
}
private function showLogin()
{
$data = $this->getlogin();
$cookieVal = "%".$getUser["user"]."%".$getUser["isadmin"]."%".$getUser["name"]."%".$getUser["surname"]."%";
createCookie($cookieVal);
header("location: ../index.php?status=1");
die();
}
}
?>