I have a site with a pop up regarding a post code its use

I have a site with a pop up regarding a post code its use the following code to generate that pop up

/**
 * Get the popup_id
 * & return
 */
function get_popup_id() {
	return 359;
}

/**
 * get popup content
 */
function get_popup_content() {
	$popup = get_post(get_popup_id());
	echo $popup->post_content;
}

/**
 * get popup array
 */
function get_pop_array() {
	$postcode_array = explode(",", get_field("postcode_array", get_popup_id()));
	return $postcode_array;
}

/**
 * Check if popup been set
 */
function check_to_see_if_postcode_is_correct() {
	if ( isset($_POST["post-code"]) ) {
		if ( in_array($_POST["post-code"], get_pop_array()) ) {
			setcookie("ALLOWED_TO_ORDER", "YES", time() + (10 * 365 * 24 * 60 * 60));
			wp_redirect("/");
		}

		if ( ! in_array($_POST["post-code"], get_pop_array()) ) {
			setcookie("ALLOWED_TO_ORDER", "NO", time() + (10 * 365 * 24 * 60 * 60));
			wp_redirect("/");
		}
	}
}

add_action("wp", "check_to_see_if_postcode_is_correct");

/**
 * if they are allowed to order
 * leave them.
 * If they arent send to page
 */
function display_message_to_people_in_wrong_postcode() {
	if (isset($_COOKIE["ALLOWED_TO_ORDER"])) {
		if ($_COOKIE["ALLOWED_TO_ORDER"] == "NO") {
			echo "<div class='postcode-message'>You aren't currently in our delivery area! <div id='show-popup-again'>Change your delivery location</div></div>";
		}

		if ($_COOKIE["ALLOWED_TO_ORDER"] == "YES") {
			echo "<div class='postcode-message extra-postcode-padding'>We deliver to your area!! </div>";
		}
	}
}
// add_action("wp", "display_message_to_people_in_wrong_postcode");   

/**
 *
 */
function dont_allow_menu() {
	if (isset($_COOKIE["ALLOWED_TO_ORDER"])) {
		if ($_COOKIE["ALLOWED_TO_ORDER"] == "NO") {
			if ( get_post_type() == "product" ) {
				wp_redirect("/");
			}
		}
	}
}
add_action("wp", "dont_allow_menu");  

?>

I didn't create the code and the issue is that I cant seem to contact the orignal developer all that I need is for the message that is displayed in the header We deliver to your area!! or sorry we don't deliver to your area to appear in a pop up like the attached image wellI would prefer if it doesnt have a code that is correct that only then the pop appears saying sorry we don't deliver to your area any help greatly appreciated.

Jade