I'm having a little trouble with the user upgrades system. I upgraded my PayPal account to premier and enabled the IPN (and directed it to payment_callback.php) but I'm still struggling.
I had a friend test the system out for me. He got moved to the specified group and I got notified of the payment via PayPal but the money wasn't added to my balance, nor was the money sent back to my friend's account (luckily it was only a cent).
It's probably right under my nose.
Thanks in advance for your help,