Doesn't the mail function require 4 parts:
mail($recipient, $subject, $content, $mailHeaders);
In your case it looks like you would be trying to send the message body as the subject.
These are the mail headers I usually send with an HTML formatted email:
$mailHeaders = "From: ".$POST['from']."<".$POST['from'].">\n";
$mailHeaders .= "Reply-To: ".$POST['from']."\n";
$mailHeaders .= "X-Mailer: PHP\n";
$mailHeaders .= "X-Sender: ".$POST['from']."\n";
$mailHeaders .= "Return-Path: ".$POST['from']."\n";
$mailHheaders .= "Cc: ".$POST['cc']."\n";
$mailHeaders .= "X-Priority: 3\n"; //1 UrgentMessage, 3 Normal
$mailHeaders .= "Content-Type: text/html; charset=iso-8859-1\n";
Just eliminate the last item if you want to send plain text format.