How could it take so long in one instance and so quick in another then? I don't want to have to give this guy the money back and then lose it because he didn't tell me it came the next day or something.
It's probably gotten lost, damaged or the bugger is a dodgy bastard looking for a refund whilst having received the package.
It's one of the reasons you register it but also one of the reasons that a buyer/receiver should ask for insurance on the package. When you've sent it, you've sent it and that's all that you can do. You can't check if he's received it and the only way to prove to him you've sent it are receipts.
I wouldn't refund him but I'd learn from the experience and take whatever schtick you're about to receive and SEND EXPRESS or REGISTERED in the future.
Now if you don't mind, I'm going to grab another Carlton Daught and watch the rest of Flight of the Concords.