<?php

  // Excerto do código
  $mail = new PHPMailer;
  $mail->IsMail();
  $mail->IsHTML(true);
  $mail->isSMTP();
  $mail->SMTPAuth = true;

  $mail->Host = 'mail.meudominio.pt';
  $mail->Username = 'valid_user@meudominio.pt';
  $mail->Password = 'abc123';

  $mail->setFrom('emaildaminhavizinha@sapo.pt', 'pomba gira');
  $mail->addReplyTo('outroemailqualquer@yahoo.com', 'yahoo guy');

?>