PHP script wont perform query : So I'm having a bit of trouble on this. I'm not sure if this information is important but this script was working at one point, but it kept making multiple records for every submission (It seemed like it was making a  submission for every inputted form value) 

eg. if first name and last name were entered, 2 records would be created. 

Besides that though, this is the code I'm having trouble with right now:

**(connection.php)**

    <?php
    $host = "localhost";
    $dbusername = "root";
    $dbpassword = "";
    $dbname = "contacts";
    $conn = new mysqli($host, $dbusername, $dbpassword, $dbname);

    if($conn)
    {
    echo "Connection OK!";
    }
    else
    {
	    die("Connection failed");
    }	
    ?>

**(index.html)**

    <?php
    include ("connection.php");

    $fn = isset ($_GET['first_name'])? $_GET['first_name'] : null;
    $ln = isset ($_GET['last_name'])? $_GET['last_name'] : null;

    $query = "INSERT INTO contact VALUES ('fn','ln')";
    $data = mysqli_query($conn, $query);

    if($data)
    {
    echo "Data inserted!";
    }
    ?>

the connection seems to be working just fine because i'm getting a "Connection OK" message, and the variables also seem to change based on the form values... but the query will not work no matter what I do now (I'm trying to fill a table with the above values if that isn't obvious)... I'm using Apollo 2.435 in case there is a plugin issue and you know how I could fix that (That also seems to be working seeing as all of the above code is working within an HTML document)

Thanks for your help.