Make sure the return url on paypal's site is correct and check the IPN notification setting at paypal. it should be set to your callback url.
To test your ipn, go to developer.paypal.com click test tools and use the ipn simulator. If that doesnt work let me know what the logs say.
To test your ipn, go to developer.paypal.com click test tools and use the ipn simulator. If that doesnt work let me know what the logs say.