WooCommerce Change User Role on Purchase of Specific Product

lgbk_add_member.php

function lgbk_add_member( $order_id ) {

$order = new WC_Order( $order_id );
$items = $order->get_items();

foreach ( $items as $item ) {
    $product_name = $item['name'];
    $product_id = $item['product_id'];
    $product_variation_id = $item['variation_id'];
}

if ( $order->user_id > 0 && $product_id == '48' ) {
	update_user_meta( $order->user_id, 'paying_customer', 1 );
	$user = new WP_User( $order->user_id );

	// Remove role
	$user->remove_role( 'customer' ); 

	// Add role
	$user->add_role( 'subscriber' );
	}
}
add_action( 'woocommerce_order_status_completed', 'lgbk_add_member' );