PHP/HTML contact form not working

Question

I've been trying to find the solution to this problem through some forums but I still can't get it to work. I have a simple PHP contact form uploaded to a website: http://proyectohales.com/anamarco

The form is the following

<form method="post" id="meetingform" name="meetingform" class="meeting-form clearfix" action="mail/meeting.php">
<input name="mname" id="mname" type="text" placeholder="Nombre" class="form-control input-lg">
<input name="memail" id="memail" type="email" placeholder="Email" class="form-control input-lg">
<input name="mphone" id="mphone" type="text" placeholder="Teléfono" class="form-control input-lg">
<textarea  name="mcase" id="mcase" placeholder="Mensaje" class="form-control input-lg"></textarea>
<button name="msubmit" id="msubmit" type="submit" class="btn btn-primary btn-block btn-lg margin-20"><i class="fa fa-send-o"></i> Enviar</button>
</form>

And the php code is:

<?php

if(!$_POST) exit;

// Email address verification, do not edit.
function isEmail($email) {
    return(preg_match("/^[-_.[:alnum:]]+@((([[:alnum:]]|[[:alnum:]][[:alnum:]-]*[[:alnum:]])\.)+(ad|ae|aero|af|ag|ai|al|am|an|ao|aq|ar|arpa|as|at|au|aw|az|ba|bb|bd|be|bf|bg|bh|bi|biz|bj|bm|bn|bo|br|bs|bt|bv|bw|by|bz|ca|cc|cd|cf|cg|ch|ci|ck|cl|cm|cn|co|com|coop|cr|cs|cu|cv|cx|cy|cz|de|dj|dk|dm|do|dz|ec|edu|ee|eg|eh|er|es|et|eu|fi|fj|fk|fm|fo|fr|ga|gb|gd|ge|gf|gh|gi|gl|gm|gn|gov|gp|gq|gr|gs|gt|gu|gw|gy|hk|hm|hn|hr|ht|hu|id|ie|il|in|info|int|io|iq|ir|is|it|jm|jo|jp|ke|kg|kh|ki|km|kn|kp|kr|kw|ky|kz|la|lb|lc|li|lk|lr|ls|lt|lu|lv|ly|ma|mc|md|me|mg|mh|mil|mk|ml|mm|mn|mo|mp|mq|mr|ms|mt|mu|museum|mv|mw|mx|my|mz|na|name|nc|ne|net|nf|ng|ni|nl|no|np|nr|nt|nu|nz|om|org|pa|pe|pf|pg|ph|pk|pl|pm|pn|pr|pro|ps|pt|pw|py|qa|re|ro|ru|rw|sa|sb|sc|sd|se|sg|sh|si|sj|sk|sl|sm|sn|so|sr|st|su|sv|sy|sz|tc|td|tf|tg|th|tj|tk|tm|tn|to|tp|tr|tt|tv|tw|tz|ua|ug|uk|um|us|uy|uz|va|vc|ve|vg|vi|vn|vu|wf|ws|ye|yt|yu|za|zm|zw)$|(([0-9][0-9]?|[0-1][0-9][0-9]|[2][0-4][0-9]|[2][5][0-5])\.){3}([0-9][0-9]?|[0-1][0-9][0-9]|[2][0-4][0-9]|[2][5][0-5]))$/i",$email));
}

if (!defined("PHP_EOL")) define("PHP_EOL", "\r\n");

$mname     = $_POST['mname'];
$memail    = $_POST['memail'];
$mphone    = $_POST['mphone'];
$mcase  = $_POST['mcase'];

if(trim($mname) == '') {
    echo '<div class="alert alert-error">Introduzca un nombre.</div>';
    exit();
} else if(trim($memail) == '') {
    echo '<div class="alert alert-error">Introduzca un email.</div>';
    exit();
} else if(!isEmail($memail)) {
    echo '<div class="alert alert-error">Introduzca un email válido.</div>';
    exit();
} else if(trim($mphone) == '') {
    echo '<div class="alert alert-error">Introduzca un número de teléfono.</div>';
    exit();
}


// Configuration option.
// Enter the email address that you want to emails to be sent to.
// Example $address = "joe.doe@yourdomain.com";

//$address = "example@websiteurl.com";
$address = "OUR MAIL GOES HERE AND IS CORRECTLY WRITTEN";


// Configuration option.
// i.e. The standard subject will appear as, "You've been contacted by John Doe."

// Example, $e_subject = '$name . ' has contacted you via Your Website.';
$e_subject = 'Contacto web Ana Marco';


// Configuration option.
// You can change this if you feel that you need to.
// Developers, you may wish to add more fields to the form, in which case you must be sure to add them here.

$e_body = "Has sido contactada por $mname" . PHP_EOL . PHP_EOL;
$e_reply = "Puedes contactar con $name por teléfono ($mphone) o email ($memail)";

$msg = wordwrap( $e_body . $e_reply, 70 );

$headers = "From: $memail" . PHP_EOL;
$headers .= "Reply-To: $memail" . PHP_EOL;
$headers .= "MIME-Version: 1.0" . PHP_EOL;
$headers .= "Content-type: text/plain; charset=utf-8" . PHP_EOL;
$headers .= "Content-Transfer-Encoding: quoted-printable" . PHP_EOL;

if(mail($address, $e_subject, $msg, $headers)) {

    // Email has sent successfully, echo a success page.

    echo "<div class='alert alert-success'>";
    echo "<h3>Email enviado con éxito.</h3><br>";
    echo "<p>Gracias. Su mensaje ha sido enviado.</p>";
    echo "</div>";

} else {

    echo 'ERROR!';

}

I don't understand why it won't work (no email is received in our inbox). Could you please help me out figure it out? Maybe it's some small detail in the code that I can't find.

Thank you!