undefined variable error when opening the page - php

Question

I am really new to coding, trying to fix this problem, but I haven't found a solution. Hopefully I can help here. This is the code :
<?php
$stock = file_get_contents("deletedforpost");
$stock2 = file_get_contents("deletedforpost");
$response = json_decode($stock);
foreach ($response as $data) {
$cc = $data->country_code;
$c = $data->country;
$i = $data->invites;
$total += $data->invites; //line 10
$data2 .= "<option value=\"$cc\">$c Remaining: $i</option>"; //line 11
}
if(isset($_POST['k'], $_POST['c'])) {
$key = $_POST['k'];
$country = $_POST['c'];
$upgrade = file_get_contents("deletedforpost");
$upgrade = json_decode($upgrade);
$status = $upgrade->status;
switch ($status){
case "success":
$token = $upgrade->data->token;
$upgrade = $upgrade->data->address;
break;
case "failure":
$failure = $upgrade->message;
break;
default:
$failure = "Unknown Error";
break;
}
}
include'include/header.php';
?>
<section class="bg-primary hero hero-with-header">
<center><div class="container text-white">
<div class="row">
<div class="col-md-12 col-lg-12">
<h1 class="mb-0">You <b>are</b> Here.</h1>
</div>
</div>
</div> </center>
</section>
<section class="bg-primary text-white separator-top">
<div class="container">
<div class="row">
<div class="col-md-6">
<h2>Enter something</h2>
</div>
</div>
<div class="row">
<div class="col">
<form method="post">
<div class="form-row">
<div class="form-group col-md-5 col-lg-6">
<input class="form-control form-control-lg" name="k" placeholder="Your Key">
</div>
<div class="form-group col-md-3 col-lg-4">
<select class="form-control form-control-lg" name="c" id="type-input">
<?=$data2?>
</select>
</div>
<div class="form-group col-md-4 col-lg-2">
<button type="submit" class="btn btn-block btn-lg btn-white">Hello</button>
</div>
</div>
</form>
</div>
</div>
</div>
<?php if ($failure) { //line 88
echo'
<div class="container text-white">
<div class="row">
<div class="col-12 mb-0">
<h2 class="eyebrow mb-2">Output:</h2>
</div>
<div class="col">
<span class="job row align-items-center">
<span class="col-md-6 fs-22 font-weight-light text-white">
Failure!
</span>
<span class="col-md-3">
Upgrade Failed '.$failure.'
</span>
<a target="_blank" href="info.php" class="col-md-3">
Click to get key info!
</a>
</span>
</div>
</div>
</div>
';}
if ($token) { //line 113
echo'
<div class="container text-white">
<div class="row">
<div class="col-12 mb-0">
<h2 class="eyebrow mb-2">Output:</h2>
</div>
<div class="col">
<span class="job row align-items-center">
<span class="col-md-6 fs-22 font-weight-light text-white">
Success!
</span>
<span class="col-md-3">
Address: '.$upgrade.'
</span>
<a target="_blank" href="'.$token.'" class="col-md-3">
Click to accept invite!
</a>
</span>
</div>
</div>
</div>
';} ?>
</section>
<?php include'include/footer.php'?>
I get this following error :
Notice: Undefined variable: total in C:\xampp\htdocs\upgrade.php on line 10
Notice: Undefined variable: data2 in C:\xampp\htdocs\upgrade.php on line 11
Notice: Undefined variable: failure in C:\xampp\htdocs\upgrade.php on line 88
Notice: Undefined variable: token in C:\xampp\htdocs\upgrade.php on line 113