Delete bogus users

I’ve got a problem with the number of fake users on my site.

There are around 3,234 users on the site, with around 2,990 fake.

I’ve written a script in php.

This script accurately echos the fake users, then puts them into an array called $dupe_ID.

I then do a foreach loop using the DELETE FROM command.

If it returns true, I ask it to iterate by one.

On execution: It does the correct number of iterations, but nothing is deleted from the database, does anyone know why?

Thanks.

<?php
$servername = "localhost";
$dbname = "michaelt****3";
$username = "michaelt***3";
$password = "P******";

// Create connection
$link = mysqli_connect($servername, $username, $password, $dbname);

// Check connection
if (!$link) {
    die("Connection failed: " . mysqli_connect_error());
}
echo "Connected successfully <br>";

//If form submitted

if ($_GET["form"] == "true") {
echo '<H1>FORM SUBMITTED</H1>';

	// select all users

	$query = "SELECT wp_users.ID FROM wp_users,wp_comments GROUP BY wp_users.ID ORDER BY wp_users.display_name asc";

	$result = $link->query($query);

	while($row = mysqli_fetch_array($result)) {

	$all_names[]=$row["ID"];

	} 

	$query = "SELECT wp_users.ID FROM wp_users,wp_comments WHERE
 	INSTR (wp_users.display_name, wp_comments.comment_author) > 0 GROUP BY wp_users.ID ORDER BY wp_users.display_name asc";

	//execute the query.

	$result = $link->query($query);

	//display information:

	while($row = mysqli_fetch_array($result)) {

	$names[]=$row["ID"];

	} 

$dupe_ID = array_diff($all_names,$names);

$i=0;

// LOOP THE COMMAND

foreach ($dupe_ID as $value) {

	// DELETE THE USERS
	$query = "DELETE FROM wp_users WHERE ID = $value";

	if (mysqli_query($link, $query)) {
   	 	$i++;
		} else {
    		echo "Error deleting records: " . mysqli_error($link);
		}

	}

	echo $i . 'Names deleted';
}

else

{

// select all users

$query = "SELECT wp_users.display_name FROM wp_users,wp_comments GROUP BY wp_users.ID ORDER BY wp_users.display_name asc";

$result = $link->query($query);

while($row = mysqli_fetch_array($result)) {

$all_names[]=$row["display_name"];

} 

$query = "SELECT wp_users.display_name FROM wp_users,wp_comments WHERE
 INSTR (wp_users.display_name, wp_comments.comment_author) > 0 GROUP BY wp_users.ID ORDER BY wp_users.display_name asc";

//execute the query.

$result = $link->query($query);

//display information:

while($row = mysqli_fetch_array($result)) {

$names[]=$row["display_name"];

} 

$dupe_names = array_diff($all_names,$names);

$i=1;

// print out the bogus names

foreach ($dupe_names as $value) {
echo $i.')'. $value .'<br>';
$i++;
}

echo '<p><h3>To delete these names click here </h3></p>';
echo '<form method="GET" target="bogus_users.php" ><input type=submit label="Destroy these entries"  value="Submit"><input type="hidden" name="form" value="true"></form>';

}

?>