为什么我的php联系人表单发送空白电子邮件

我是一个PHP新手，想知道是否有人在那里有技能谁可以帮助我这个?一旦用户(在本例中是我)提交了信息，它就会向我的收件箱发送空白电子邮件。而且，也没有主体出现。我相信我的问题是不同的，因为它的特定代码增加了无线电功能，这有助于我更好地理解它，并从我的错误中吸取教训。提前谢谢。

My PHP Code:

<?php
if(!isset($_POST['submit'])) {
    //This page should not be accessed directly. Need to submit the form.
    echo "error; you need to submit the form!";
}
$name = $_POST['name'];
$email = $_POST['email'];
$tel = $_POST['tel'];
$message = $_POST['message'];
$email_from = 'testtike@yahoo.com'; //<== update the email address
$email_subject = "New Form submission";
$email_body =   "You have received a new message from the user $name.'n" 
                . "Here is the message:'n $message".
$to = "testtike@yahoo.com"; //<== update the email address
$headers = "From: $email_from 'r'n";
$headers .= "Reply-To: $visitor_email 'r'n";
//Send the email!
mail($to, $subject, $body, $from, $tel);
//done. redirect to thank-you page.
header('Location: thank-you.html');

// Function to validate against any email injection attempts
function IsInjected($str) {
    $injections = array('
        ('n+)',
        '('r+)',
        '('t+)',
        '(%0A+)',
        '(%0D+)',
        '(%08+)',
        '(%09+)'
    );
    $inject = join('|', $injections);
    $inject = "/$inject/i";
    if(preg_match($inject,$str)) {
        return true;
    } else {
        return false;
    }
}

我的HTML。

<label>Name</label>
<input name="name" placeholder="Type Here">
<label>Email</label>
<input name="email" type="email" placeholder="Type Here">
<label>Phone Number</label>
<input name="tel" type="phone" placeholder="Type Here">
<label>Message/Comments/Questions</label>
<textarea name="message" placeholder="Type Here"></textarea>

<label>Are you retired?</label> <br>
<div id="button">
<input type="radio" name="retired" value="yes"> Yes.
<input type="radio" name="retired" value="no"> No. 
<input type="radio" name="retired" value="na"> Does not apply.<br><br>
</div>

<label>Are you a veteran?</label> <br>
<div id="button">
<input type="radio" name="vet" value="yes"> Yes.
<input type="radio" name="vet" value="no"> No. 
<input type="radio" name="vet" value="na"> Does not apply.<br><br>
</div>

<label>Military Family Member?</label> <br>
<div id="button">
<input type="radio" name="family" value="yes"> Yes.
<input type="radio" name="family" value="no"> No. 
<input type="radio" name="family" value="na"> Does not apply.<br>
</div>
<label> Do You Have A Copy of Your DD214?</label> <br>
<div id="button">
<input type="radio" name="dd" value="yes"> Yes.
<input type="radio" name="dd" value="no"> No. 
<input type="radio" name="dd" value="na"> Does not apply.<br>
</div>
<input type="submit" name='submit' value="submit">

</form>