I am developing an auction website. When a person intents to pay for an auction item, I pass his email_id and that of the seller to Paypal and then invoke IPN through notify_url. Once he pays the data is sent to my IPN listener so that I process and update the database. My question is; since I am a third party, if the seller has disabled IPN will I receive the variables on my IPN listener? If not how else can I ensure that I get confirmation of payment and process the database. I cant use return_url because it is dependent on whether the buyer returns to my site.