PHP - Agregar todo el contenido en el mensaje de contacto PHP

<div class="row">

    <div class="col-md-10 col-md-offset-1">

      <div class="contact-form sep-top-lg">

        <div id="successMessage" style="display:none" class="alert alert-success text-center">

          <p><i class="fa fa-check-circle fa-2x"></i></p>

          <p>Thanks for sending your message! We'll get back to you shortly.</p>

        </div>

        <div id="failureMessage" style="display:none" class="alert alert-danger text-center">

          <p><i class="fa fa-times-circle fa-2x"></i></p>

          <p>There was a problem sending your message. Please, try again.</p>

        </div>

        <div id="incompleteMessage" style="display:none" class="alert alert-warning text-center">

          <p><i class="fa fa-exclamation-triangle fa-2x"></i></p>

          <p>Please complete all the fields in the form before sending.</p>

        </div>

        <form id="contactForm" action="php/contact.php" method="post" class="validate">

          <div class="row">

            <div class="col-md-6 sep-top-xs">

              <div class="form-group">

                <label for="name" class="upper">Your Name</label>

                <input id="name" type="text" placeholder="Enter name" name="senderName" class="form-control input-lg required">

              </div>

            </div>

            <div class="col-md-6 sep-top-xs">

              <div class="form-group">

                <label for="email" class="upper">Your Email</label>

                <input id="email" type="email" placeholder="Enter email" name="senderEmail" class="form-control input-lg required email">

              </div>

            </div>

          </div>

          <div class="row">

            <div class="col-md-6 sep-top-xs">

              <div class="form-group">

                <label for="phone" class="upper">Your Phone</label>

                <input id="phone" type="text" placeholder="Enter phone" name="phone" class="form-control input-lg required">

              </div>

            </div>

            <div class="col-md-6 sep-top-xs">

              <div class="form-group">

                <label for="company" class="upper">Your Company</label>

                <input id="company" type="text" placeholder="Enter company" name="company" class="form-control input-lg required">

              </div>

            </div>

          </div>

          <div class="row">

            <div class="col-md-12 sep-top-xs">

              <div class="form-group">

                <label for="comment" class="upper">Your comment</label>

                <textarea id="comment" placeholder="Enter comment" rows="9" name="comment" class="form-control input-lg required"></textarea>

              </div>

            </div>

          </div>

          <div class="row">

            <div class="col-md-12 sep-top-xs">

              <div class="form-group text-center">

                <button type="submit" class="btn btn-primary"><i class="fa fa-paper-plane"></i>&nbsp;Send message</button>

              </div>

            </div>

          </div>

          <!--input#subject.form-control.input-lg.required(type='text', placeholder='Subject of your message', name='subject')

<?php

header('Access-Control-Allow-Headers: x-requested-with');

header('Access-Control-Allow-Origin: *');

// Define some constants

define( "RECIPIENT_NAME", "NAME" );

define( "RECIPIENT_EMAIL", "EMAIL" );

define( "EMAIL_SUBJECT", "SUBJECT" );

// Read the form values

$success      = false;

//$xhr          = isset($_SERVER['HTTP_X_REQUESTED_WITH']) && (strtolower($_SERVER['HTTP_X_REQUESTED_WITH']) == 'xmlhttprequest');

$xhr          = isset( $_POST['ajax'] )

              ? true

              : false;

$senderName   = isset( $_POST['senderName'] )

              ? preg_replace( "/[^\.\-\' a-zA-Z0-9]/", '', $_POST['senderName'] )

              : '';

$senderEmail  = isset( $_POST['senderEmail'] )

              ? preg_replace( "/[^\.\-\_\@a-zA-Z0-9]/", '', $_POST['senderEmail'] )

              : '';

$subject      = isset( $_POST['subject'] )

              ? preg_replace( "/(From:|To:|BCC:|CC:|Subject:|Content-Type:)/", '', $_POST['subject'] )

              : EMAIL_SUBJECT;

$comment      = isset( $_POST['comment'] )

              ? preg_replace( "/(From:|To:|BCC:|CC:|Subject:|Content-Type:)/", '', $_POST['comment'] )

              : '';

// If all values exist, send the email

if ( $senderName && $senderEmail && $comment ) :

  $recipient = RECIPIENT_NAME . " <" . RECIPIENT_EMAIL . ">";

  $headers = "From: " . $senderName . " <" . $senderEmail . ">";

  try {

    mail( $recipient, $subject, $comment, $headers );

    $success = 'success';

  } catch (Exception $e) {

    $success = $e->getMessage();

  }

else:

  $success = 'error: incomplete data';

endif;

// Return an appropriate response to the browser

if ( $xhr ) : // AJAX Request

  echo $success;

else : // HTTP Request ?>

<!doctype html>

<html>

  <head>

    <title>Thanks!</title>

  </head>

  <body>

    <p>

    <?php

      if ( $success == 'success') :

        echo "<p>Thanks for sending your message! We'll get back to you shortly.</p>";

      else :

        echo "<p>There was a problem sending your message. Please try again.</p>";

      endif;

    ?>

    </p>

    <p>Click your browser's Back button to return to the page.</p>

  </body>

</html>

<?php endif; ?>

// Aquí coges el teléfono

$phone= isset( $_POST['phone'] )

? $_POST['phone']  : '';

// Aquí coges la empresa

$company= isset( $_POST['company'] )

? $_POST['company']  : '';

// Aquí añadimos el teléfono y la compañía al texto del mensaje

$comment="Company: ". $company."\nPhone: ".$phone."\n".$comment;