Formulario envio mail

[gustax]

Y tengo otro archivo que se llama contactusform.php:
Que ademas del formulario, contiene el siguiente apartado donde estan definidas las variables:

Código PHP:

      if(($_POST)&&($errors == 0)){
        $form = "";
        $message = "";
        if($_POST['title'] != ""){
            $message .= $title_label." ".$_POST['title']."\n";
        }
        if($_POST['firstname'] != ""){
            $message .= $first_name_label." ".$_POST['firstname']."\n";
        }
        if($_POST['middlename'] != ""){
            $message .= $middle_name_label." ".$_POST['middlename']."\n";
        }
        if($_POST['lastname'] != ""){
            $message .= $last_name_label." ".$_POST['lastname']."\n";
        }
        if($_POST['company'] != ""){
            $message .= $company_label." ".$_POST['company']."\n";
        }
        if($_POST['direccion'] != ""){
            $message .= $direccion_label." ".$_POST['direccion']."\n";
        }
        if($_POST['ciudad'] != ""){
            $message .= $ciudad_label." ".$_POST['ciudad']."\n";
        }
        if($_POST['provincia'] != ""){
            $message .= $provincia_label." ".$_POST['provincia']."\n";
        }
        if($_POST['state'] != ""){
            $message .= $state_label." ".$_POST['state']."\n";
        }
        if($_POST['zipcode'] != ""){
            $message .= $zipcode_label." ".$_POST['zipcode']."\n";
        }
        if($_POST['country'] != ""){
            $message .= $country_label." ".$_POST['country']."\n";
        }
        if($_POST['telephone'] != ""){
            $message .= $telephone_label." ".$_POST['telephone']."\n";
        }
        if($_POST['fax'] != ""){
            $message .= $fax_label." ".$_POST['fax']."\n";
        }
        if($_POST['email'] !=""){
            $message .= $email_label." ".$_POST['email']."\n";
        }
        if($_POST['dominio'] != ""){
            $message .= $dominio_label." ".$_POST['dominio']."\n";
        }
        if($_POST['subject'] != ""){
            $message .= $subject_label." ".$_POST['subject']."\n";
        }
        if($_POST['reference'] != ""){
            $message .= $reference_label." ".$_POST['reference']."\n";
        }
        $message .= $message_label." ".$_POST['message']."\n";
        
        $message = str_replace("\n.", "\n..", $message);
        $to  = $mail_to;
        $subject = "Contrato de servicio en www.arteg.com.ar";
        $headers = 'From: Arteg - Internet Solutions <'.$_POST['email'].'>' . "\r\n";

        if(!mail($to, $subject, $message, $headers)){
            $errors++;
        }

        $message = $receipt_insert_top."\n".$message."\n".$receipt_append_bottom;
        $message = str_replace("\n.", "\n..", $message);
        $to      = $_POST['email'];
        $subject = $_POST['subject'];
        $headers = 'To: '.$_POST['firstname'].' '.$_POST['lastname'].' <'.$_POST['email'].'>' . "\r\n";
        $headers .= 'From: '.$website_name.' <'.$mail_from.'>' . "\r\n";
        
        
        if(($send_a_receipt_to_sender)&&($show_email_filed)&&($_POST['email'] !="")){
            if(!mail($to, $subject, $message, $headers)){
                $errors++;
            }
        }
        

        if($errors){
            $form = $message_on_submit_error;
        }
        else
            $form = $message_after_submit_success;
        
    
            
    }

function showcontactusform(){
    global $form;echo $form;
}