I'm writing this here, as It's my first time refunding a customer due the simple fact that he set only one pool which went dead. I've emailed him - no answer so, i don't want to be guilty of a dead rig... so i'm refunding him his BTC in full. (https://blockchain.info/tx/0e208f026c74d9b3af597424bbe40a62872f03694a2a0e2eef97276cab1ed6a3)

@Djezo: Correct me if this is not the best way.