Send Email to Custom Field in Custom Post Type when order is Completed

How to debug

Step 1

add_filter( 'woocommerce_email_headers', 'enyc_order_completed_email_add_cc_bcc', 10, 3 );
function enyc_order_completed_email_add_cc_bcc( $headers, $email_id, $order ) { 
    // CHANGE EMAIL
    $partnerEmail="[email protected]";

    $headers .= 'Cc: Name <'.$partnerEmail.'>' . '\r\n'; // del if not needed
    $headers .= 'Bcc: Name <[email protected]>' . '\r\n'; // del if not needed

    return $headers;
}

Step 1 works? -> step 2

add_filter( 'woocommerce_email_headers', 'enyc_order_completed_email_add_cc_bcc', 10, 3 );
function enyc_order_completed_email_add_cc_bcc( $headers, $email_id, $order ) {
    // CHANGE ID
    $product_id = 100;

    //Get Partner Data from Product
    $partner = get_field( 'venue', $product_id);

    //Get Partner ID
    $partnerID = $partner->ID;

    //Get Partner Email
    $partnerEmail = get_field( 'partner_email', $partnerID);

    $headers .= 'Cc: Name <'.$partnerEmail.'>' . '\r\n'; // del if not needed
    $headers .= 'Bcc: Name <[email protected]>' . '\r\n'; // del if not needed

    return $headers;
}

Step 3, etc..