页面重定向不工作PHP

Im trying to redirect my user when they click "Empty Cart". The redirect is working with my "Add to cart" but not for "Empty cart". Any ideas would be great.

In my main .php file i set the current url as seen

$current_url = base64_encode("http://$_SERVER[HTTP_HOST]$_SERVER[REQUEST_URI]");

Then below is my cartAction.php file that handles actions such as "Add to cart" and "Empty cart"

<?php
session_start();
include_once 'config.php';

//add item in shopping cart
if(isset($_POST["add"])) {
    $product_id = $_POST["product_id"]; //product id
    $return_url = base64_decode($_POST["return_url"]); //return url
    $qty = $_POST["qty"];
    $product = $mysqli->query("SELECT product_name, unit_price, unit_quantity FROM products WHERE product_id = '$product_id'");
    $obj = $product->fetch_object();

    if(!isset($_SESSION['products'])) {
        $_SESSION['products'] = array();
    }

    if(array_key_exists($product_id, $_SESSION['products'])) {
        $_SESSION['products'][$product_id]['qty'] += $qty;
        //redirect back to original page
        header('Location:'.$return_url);
    }
    else {
        $_SESSION['products'][$product_id] = array('name' => $obj->product_name, 'price' => $obj->unit_price, 'unit' => $obj->unit_quantity, 'qty' => $qty); 
    }

    //redirect back to original page
    header('Location:'.$return_url);
}

//empty cart by distroying current session
if(isset($_POST["emptycart"]))
{
    $return_url = base64_decode($_POST["return_url"]); //return url
    session_destroy();
    header('Location:'.$return_url);
}
?>

"Are you sure that $_POST['return_url'] is set? Try to var_dump it and check its value. " @OfirBaruch

"error_reporting(E_ALL); ini_set('display_errors', 1); at the top of your php. Guarantee you'll have something useful." @Devon

Above are the appropriate answers/approaches to the problem.