How to fix message not shown in email activation - php

Question

I can't seem to get my email activation message to be sent in my new host called infinity-free.
I tried to use phpmailer as well as the mail function but can't see my html content.
$to = $email;
//sender
$from = 'pianocourse101#hotmail.com';
$fromName = 'PianoCourse101';
//email subject
$subject = 'Activate your Primer Level Membership Plan!';
//attachment file path
$file = "codexworld.pdf";
//email body content
$htmlContent = "<h1>Activate your Primer Level Membership Plan!</h1>
<p>Dear $first $last, <br />Thank you for registering your Primer Level Membership Plan with PianoCourse101! You are receiving this e-mail because you or someone else claiming to be you has selected a Primer Level Membership Plan \n\nIf you believe that this is a mistake, please send us a ticket with the subject \"How to cancel my Primer Level Membership Plan?\" and allow at least 48 hours before receiving a reply.\n\nHowever, if this is correct, then you must activate your Primer Level Membership Plan by clicking on the link below: \n\n Click here to activate your Primer Level Membership Plan.\n\nAlternatively, you can use the following token to manually activate your Level 3 Yearly Membership Plan by clicking on the 'Activate Membership\s Section:' \n\nToken:.$token4;
</p>";
//header for sender info
$headers = "From: $fromName"." <".$from.">";
//boundary
$semi_rand = md5(time());
$mime_boundary = "==Multipart_Boundary_x{$semi_rand}x";
//headers for attachment
$headers .= "\nMIME-Version: 1.0\n" . "Content-Type: multipart/mixed;\n" . " boundary=\"{$mime_boundary}\"";
//multipart boundary
$message = "--{$mime_boundary}\n" . "Content-Type: text/html; charset=\"UTF-8\"\n" .
"Content-Transfer-Encoding: 7bit\n\n" . $htmlContent . "\n\n";
//preparing attachment
if(!empty($file) > 0){
if(is_file($file)){
$message .= "--{$mime_boundary}\n";
$fp = #fopen($file,"rb");
$data = #fread($fp,filesize($file));
#fclose($fp);
$data = chunk_split(base64_encode($data));
$message .= "Content-Type: application/octet-stream; name=\"".basename($file)."\"\n" .
"Content-Description: ".basename($file)."\n" .
"Content-Disposition: attachment;\n" . " filename=\"".basename($file)."\"; size=".filesize($file).";\n" .
"Content-Transfer-Encoding: base64\n\n" . $data . "\n\n";
}
}
$message .= "--{$mime_boundary}--";
$returnpath = "-f" . $from;
//send email
$mail = mail($to, $subject, $message, $headers, $returnpath);
//email sending status
echo $mail?"<h1>Mail sent.</h1>":"<h1>Mail sending failed.</h1
>";
I have also used phpmailer with similar contents but can't seem to get it send through....