I did not sell him a 'Duff' PSU!! It was working when i sent it out. I tested it in a PC and it started fine and i tested it with a PSU tester. All was fine.
I have said i will give a full refund if he returns it and it is not working. Nothing more i can do. I am a honest guy and stand by my word. Look at my Hexus Trust. If this is going to turn into a thread of bad words then i would suggest it gets closed and let me get the PSU to test it. Thanks.