What happens if you refuse to cancel the order ?
Surely if something is advertised at X price, they accept an order for it, they have to honour the sale ?
It was a obvious typo, and the terms of sale that the customer agreed to specified that the sale could be cancelled and money refunded. Its wishful thinking to think that they would give away some very expensive equipment over a Typo.
I had the same thing happen to me, I ordered a 7D the day they were announced, and a few weeks later, Amazon.com cancelled my order because their price was wrong by about $200. This wasn't a obvious typo, they just speculated on the actual price and started taking orders. Pretty sleezy. They didn't even give me the option of paying that extra for it, so I lost my place in line for a early delivery.
I ordered from Adorama instead.