PHP form with checkbox and verification does't work - php

Question

i"m new here and i don't understand php at all, but i need to do a contact form with checkbox and verification, this is my code ( is a frankenstein code).
I need that my form send an email with the information avoiding spam, and missing information, and when mail arrive has all the details in header like a mail to reply, subject and all.
if you can post an correct code will be wonderful.
thanks in advance
<form name="htmlform" method="post" action="app.php">
<label for="name">*Nombre Completo</label>
<input type="text" name="name" maxlength="150" size="50">
<label for="company">*Empresa</label>
<input type="text" name="company" maxlength="150" size="50">
<label for="telephone">Teléfono</label>
<input type="text" name="telephone" maxlength="150" size="50">
<label for="email">*Email</label>
<input type="text" name="email" maxlength="180" size="50">
<label for="services">*Servicios de Interes</label>
<input type="checkbox" name="services[]" value="apps" />apps<br />
<input type="checkbox" name="services[]" value="Marketing Movil" />Marketing Móvil<br />
<input type="checkbox" name="services[]" value="video juegos" />video Juegos<br />
<label for="comments">*Comentarios</label>
<textarea name="comments" maxlength="1000" cols="40" rows="6"></textarea>
<div class="hide">Leave this empty:<input name="url" /></div>
<center><input class="button large" type="submit" value="Submit Form"></center>
</form>
<?php
// if the url field is empty
if(isset($_POST['url']) && $_POST['url'] == '')
if(isset($_POST['email'])) {
// EDIT THE 2 LINES BELOW AS REQUIRED
$email_to = "my#mail.com";
$email_subject = "Contact from web.com";
function died($error) {
// your error code can go here
echo "There were error(s) found with the form you submitted. ";
echo "These errors appear below.<br /><br />";
echo $error."<br /><br />";
echo "Please go back and fix these errors.<br /><br />";
die();
}
// validation expected data exists
if(!isset($_POST['full_name']) ||
!isset($_POST['email']) ||
!isset($_POST['telephone']) ||
!isset($_POST['services']) ||
!isset($_POST['comments']))
{
died('We are sorry, but there appears to be a problem with the form you submitted.');
}
$full_name = $_POST['full_name']; // required
$email_from = $_POST['email']; // required
$telephone = $_POST['telephone']; // required
$services = $_POST['services']; // required
$comments = $_POST['comments']; // required
$error_message = "";
$email_exp = '/^[A-Za-z0-9._%-]+#[A-Za-z0-9.-]+\.[A-Za-z]{2,4}$/';
if(!preg_match($email_exp,$email_from)) {
$error_message .= 'The Email Address you entered does not appear to be valid.<br />';
}
$string_exp = "/^[A-Za-z .'-]+$/";
if(!preg_match($string_exp,$full_name)) {
$error_message .= 'The First Name you entered does not appear to be valid.<br />';
}
if(strlen($comments) < 2) {
$error_message .= 'The Comments you entered do not appear to be valid.<br />';
}
if(strlen($error_message) > 0) {
died($error_message);
}
$email_message = "Form details below.\n\n";
function clean_string($string) {
$bad = array("content-type","bcc:","to:","cc:","href");
return str_replace($bad,"",$string);
}
$email_message .= "Full Name: ".clean_string($full_name)."\n";
$email_message .= "Email: ".clean_string($email_from)."\n";
$email_message .= "Telephone: ".clean_string($telephone)."\n";
$email_message .= "Services: ".clean_string($services)."\n";
$email_message .= "Comments: ".clean_string($comments)."\n";
// create email headers
$headers = 'From: '.$email_from."\r\n".
'Reply-To: '.$email_from."\r\n" .
'X-Mailer: PHP/' . phpversion();
#mail($email_to, $email_subject, $email_message, $headers);
// hacker defense
function clean($var){//request string cleaner
if(get_magic_quotes_gpc()) $var=stripslashes($var); //clean
$var=mysql_real_escape_string($var); //clean
return strip_tags($var, '<b><a>');//returning clean var
}
function hackerDefense(){//thanks to Allen Sanford
// begin hacker defense
foreach ($_POST as &$postvalue){ //checking posts
$postvalue = clean($postvalue);//cleaning the value
}
} // end hacker defense
?>
<!-- include your own success html here -->
<center>
<img src="images/logo.png" />
<br>
<br>
Thank you for contacting us. We will be in touch.<br>
<br>
HOME</center>
<?php
}
?>