OOP PHP taking content from forms created by a loop - php

Question

I'm using OOP PHP right now, and I created a few functions that pass data from a form and insert them into the database. I know all those functions work properly, but the forms in a loop wont seem to be pass.
Here's an example of how it looks:
//Input class://
<?php
class Input{
public static function exists($type='post'){
switch($type){
case 'post':
return (!empty($_POST)) ? true : false;
break;
case 'get':
return (!empty($_POST)) ? true : false;
break;
default:
return false;
break;
}
}
public static function get($item){
if(isset($_POST[$item])){
return $_POST[$item];
}else if(isset($_GET[$item])){
return $_GET[$item];
}
return '';
}
}
?>
//----------------------------------//
<?php $user = new User();
$user_id = $user->data->id; ?>
//some html//
<?php
foreach($products->results() as $row){
$pid = $row->id;
$product = $row->product;
$days = $row->days_default;
$description = $row->description;
$img = $row->img_address;
$category = $row->category;
$x++;
?>
<h4 class="item-title"><?php echo $product . $pid?></h4>
<h5 class="item-subtitle"><?php echo $category ?></h5>
<span class="timing"><?php echo $days . " days" ?></span>
<div class="itme-description"><?php echo $description ?></div>
<div>
<form action="" method="post">
<input type="hidden" name="product_id" id="product_id" value= "<?php $pid ?>">
<input type="hidden" name="days" id="days" value="<?php $days ?>">
<input type="hidden" name="user_id" id="user_id" value="<?php $user_id ?>">
<input type="submit">
</form>
</div>
<?php
if(Input::exists()){
$reminder = new Reminder();
try{
$reminder->create(
array( 'product_id'=>Input::get('product_id'),
'days'=>Input::get('days'),
'user_id'=> Input::get('user_id')));
}catch(exception $e){
die($e->getMessage());}
}
}
?>
I can't figure out how to pass the individuals forms to the server when the user hits submit.