[Plugin: WP Invoices Ultimate] IPN data not coming in

Im having problems with IPN data not coming back. The plugin works great and i love it but when a payment is made the invoice is not updated with the payment amount. I have specified the website URL as the IPN on Paypal http://www.speedyplumb.com.au im assuming this is correct. Looking through the transactions in paypal the IPN message status is sent though when i look at the WP Invoices Ultimate IPN log there is nothing.

Any help would be great, i’d really like to use this plugin.

Thanks

Marcel