undefined variable error when opening the page

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