I don't think there's anything wrong with your function.
However, I noticed that Gmail is quite picky when it comes which emails come trough to inbox:
- All Global Configuration > Server > Mail Settings must be filled in and valid.
- These settings have to be used for JMail configuration
// Initialize some variables
$app = JFactory::getApplication();
$mailer = JFactory::getMailer();
// Get mailer configuration
$mailfrom = $app->getCfg('mailfrom');
$fromname = $app->getCfg('fromname');
$sitename = $app->getCfg('sitename');
// Clean the email data
$contact_to = JMailHelper::cleanAddress( $data['contact_to'] );
$subject = JMailHelper::cleanSubject( $data['contact_subject'] );
$body = JMailHelper::cleanBody( $data['contact_message'] );
$reply_to_email = JMailHelper::cleanAddress( $data['contact_reply_to'] );
$reply_to_name = JMailHelper::cleanLine( $data['contact_reply_to_name'] );
// Construct mailer
$mailer
->addRecipient($contact_to)
->addReplyTo(array($reply_to_email, $reply_to_name))
->setSender(array($mailfrom, $fromname))
->setSubject($sitename . ': ' . $subject)
->setBody($body)
;
// Send email
$sent = $mailer->Send();