Paypal IPN & updating database dilemma - php

Question

So I have a problem and dont know what way to approach it. What I am trying to do so when the user verifies there email they are directed to a page where they select the membership plan and then they are directed to paypal to proceed with the payment - the payment field in the DB is then updated. They are then redirecting back to the website.
Problem 1: I have PayPal IPN PHP page witch is so-pose to handle the problem but that does not seem to be working or not even being called i dont know. I do have the ipn enabled and configured in the PayPal acount
<?php
// STEP 1: Read POST data
// reading posted data from directly from $_POST causes serialization
// issues with array data in POST
// reading raw POST data from input stream instead.
$raw_post_data = file_get_contents('php://input');
$raw_post_array = explode('&', $raw_post_data);
$myPost = array();
foreach ($raw_post_array as $keyval) {
$keyval = explode ('=', $keyval);
if (count($keyval) == 2)
$myPost[$keyval[0]] = urldecode($keyval[1]);
}
// read the post from PayPal system and add 'cmd'
$req = 'cmd=_notify-validate';
if(function_exists('get_magic_quotes_gpc')) {
$get_magic_quotes_exists = true;
}
foreach ($myPost as $key => $value) {
if($get_magic_quotes_exists == true && get_magic_quotes_gpc() == 1) {
$value = urlencode(stripslashes($value));
} else {
$value = urlencode($value);
}
$req .= "&$key=$value";
}
// STEP 2: Post IPN data back to paypal to validate
$ch = curl_init('https://www.paypal.com/cgi-bin/webscr'); // change to [...]sandbox.paypal[...] when using sandbox to test
curl_setopt($ch, CURLOPT_HTTP_VERSION, CURL_HTTP_VERSION_1_1);
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_RETURNTRANSFER,1);
curl_setopt($ch, CURLOPT_POSTFIELDS, $req);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 1);
curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 2);
curl_setopt($ch, CURLOPT_FORBID_REUSE, 1);
curl_setopt($ch, CURLOPT_HTTPHEADER, array('Connection: Close'));
// In wamp like environments that do not come bundled with root authority certificates,
// please download 'cacert.pem' from "http://curl.haxx.se/docs/caextract.html" and set the directory path
// of the certificate as shown below.
// curl_setopt($ch, CURLOPT_CAINFO, dirname(__FILE__) . '/cacert.pem');
if( !($res = curl_exec($ch)) ) {
// error_log("Got " . curl_error($ch) . " when processing IPN data");
curl_close($ch);
exit;
}
curl_close($ch);
// STEP 3: Inspect IPN validation result and act accordingly
// check whether the payment_status is Completed
// check that txn_id has not been previously processed
// check that receiver_email is your Primary PayPal email
// check that payment_amount/payment_currency are correct
// process payment
// assign posted variables to local variables
$item_name = $_POST['item_name'];
$item_number = $_POST['item_number'];
$payment_status = $_POST['payment_status'];
if ($_POST['mc_gross'] != NULL)
$payment_amount = $_POST['mc_gross'];
else
$payment_amount = $_POST['mc_gross1'];
$payment_currency = $_POST['mc_currency'];
$txn_id = $_POST['txn_id'];
$receiver_email = $_POST['receiver_email'];
$payer_email = $_POST['payer_email'];
$custom = $_POST['custom'];
// Insert your actions here
include 'base.php';
$q = "SELECT * FROM users WHERE EMAIL ='$email'";
//Run Query
$result = $link->query($q) or die(mysqli_error($mysqli));
//Numbers of rows that match
$num_rows = $result->num_rows;
if($num_rows > 0){
$query = "UPDATE 'users' SET 'payment' ='$payment_amount' WHERE EMAIL ='$payer_email'";
$link->query($query) or die(mysqli_error($mysqli));
if($link){
echo "<script>console.log( 'success '');</script>";
}
}else{
}
?>
Problem 2 Even if this wont there be a problem is the user used someone else account for a different email.
If any one had the patients to stick with me a read this far thanks, Any help would be great.
Regards
Amy