No emails sent via PHP Mail() function

[kwongger]

I am building a webpage with a contact form that sends an email to me via the Mail() php function.

I can send/receive emails fine via Roundcube, but none are sent via this method.  

Here is my script:

contact page:

Code:

<form  action="mail_handler.php" method="post" class="col s12">
           <div class="row">
             <div class="input-field col s6">
               <input id="name" type="text" class="validate">
               <label for="name">Name</label>
             </div>
           </div>
           <div class="row">
             <div class="input-field col s6">
               <input id="email" type="email" class="validate">
               <label for="email">Email Address</label>
             </div>
             <div class="input-field col s6">
               <input id="telephone" type="tel" class="validate">
               <label for="telephone">Telephone Number</label>
             </div>
           </div>
             <div class="row">
               <div class="input-field col s12">
                 <textarea id="message" class="materialize-textarea"></textarea>
                 <label for="message">Breif description of work to be done.</label>
               </div>
             </div>
             <div class="row">
               <div class="input-field col s6">
                 <select>
                   <option value="" disabled selected>Choose the best way to contact you</option>
                   <option value="email">Email</option>
                   <option value="telephone">Telephone</option>
                 </select>
                 <label>Best Contact Method</label>
               </div>
               <div class="input-field col s6">
                 <button class="btn waves-effect waves-light" type="submit" name="action">Submit
                   <i class="material-icons right">send</i>
                 </button>
               </div>
             </div>
           </form>

php page:

Code:

<?php
if(isset($_POST['submit'])){
   $to = "myemailishere"; // this is your Email address
   $from = $_POST['email']; // this is the sender's Email address
   $name = $_POST['name'];
   $telephone = $_POST['telephone'];
   $contactmethod = $_POST['contactmethod'];
   $subject = "Form submission";
   $subject2 = "Copy of your form submission";
   $message = $name . " wrote the following:" . "\n\n" . $_POST['message'];
   $message2 = "Here is a copy of your message " . $name . "\n\n" . $_POST['message'];

   $headers = "From:" . $from;
   $headers2 = "From:" . $to;
   mail($to,$subject,$message,$telephone,$contactmethod,$headers);
   mail($from,$subject2,$message2,$headers2); // sends a copy of the message to the sender
   echo "Mail Sent. Thank you " . $name . ", we will contact you shortly.";
   // You can also use header('Location: thank_you.php'); to redirect to another page.
   // You cannot use header and echo together. It's one or the other.
   }
?>

Any ideas?  I'm not receiving any emails whether I specify the 'to' email as my personal email (hosted on protomail) or an email I have on round cube.