This is why you can now buy Asus products from OCUK so you get the
new enhanced warranty service. The poor customer service reputation from Asus has never put me off and never will. I have never had any problems with any of their boards or gpu's and the new agreement with OCUK means that OCUK get's my money the next time I buy Asus. No use to the OP though.
I would be fighting that tooth and nail. I have never even seen anything in any of their products about registering for warranty and didn't even know that you could because it's always been dealt with through the place of purchase. I don't suppose he paid for the board by credit card by any chance? If he did then get the credit card company involved. Even some debit cards have a similar service I believe.