Have you entered an email address in osCommerce admin --> My Store, where it says 'Send extra order emails to'?
If you have, and you use Pay Pal then:
Pay Pal Standard Module
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If you are using the default Pay Pal Module that comes with
osCommerce and are wondering why the orders don't get added
to the database, the stock updated, and that no order
confirmation e-mails get sent out - this is the reason.
You are reliant upon the customer hitting the 'Continue'
button on the Pay Pal website at the end of their purchase,
which then returns them to your website, updates the database,
updates the stock quantity, empties their shopping cart,
and sends the order confirmation e-mails out.
There are two solutions:
1. Use the official osCommerce Pay Pal IPN. This is the
only IPN module which begins with 'osCommerce'. It is
also the only IPN module with a completely new and
free-standing set of files - meaning that you don't
have to edit any other files in order to install it.
2. Go to your Pay Pal account, go to Profile, and
sign up for their Auto-Return service - which returns the
customer to your website automatically after a delay of a
few seconds. The return url you must provide is something
like this (adjust as necessary for your website):
http://www.yourdomain.com/checkout_process.phpVger
