Sending email using smtp gmail in phpmailer - php

Question

I tried sending email using smtp gmail using phpmailer. My gmail account got suspended saying that there is an unusual activity. Here is the code I have used for sending emails. What's the correct way of sending emails using smtp gmail in phpmailer?
My question is not duplicate. I have already tried this : Send email using the GMail SMTP server from a PHP page
I'm using phpmailer, and my accounts getting suspended.
<?php
include('phpmailer.php');
class Mail extends PhpMailer
{
// Set default variables for all new objects
public $From = 'noreply#exmaple.org';
public $FromName = SITETITLE;
public $Host = 'smtp.gmail.com';
public $Mailer = 'smtp';
public $SMTPAuth = true;
public $Username = 'username#gmail.com';
public $Password = 'password';
public $SMTPSecure = 'tls';
public $WordWrap = 75;
public function subject($subject)
{
$this->Subject = $subject;
}
public function body($body)
{
$this->Body = $body;
}
public function send()
{
$this->AltBody = strip_tags(stripslashes($this->Body))."\n\n";
$this->AltBody = str_replace(" ", "\n\n", $this->AltBody);
return parent::send();
}
}
Here is my php code :
$to = $_POST['email'];
$subject = "Registration Confirmation";
$body = "<p>Thank you for registering at demo site.</p>
<p>To activate your account, please click on this link: <a href='".DIR."activate.php?x=$id&y=$activasion'>".DIR."activate.php?x=$id&y=$activasion</a></p>
<p>Regards Site Admin</p>";
$mail = new Mail();
$mail->setFrom('noreply#example.org');
$mail->addAddress($to);
$mail->subject($subject);
$mail->body($body);
$mail->send();
//redirect to index page
header('Location: index.php?action=joined');
exit;