Seems to be a common occurrence, I applied for the platinum card via quidco, for some reason it did not track, raised a query and now being told that amex have declined to pay. The card cost me £195 per year and the only reason going via quidco was for the cashback. I was accepted and have been using the card and you can clearly see that I went to Amex's site via quidco as the time of access and getting the acknowledge email from amex match in terms of date and time.
Now being told by quidco that there is nothing they can do. All very strange but I plan to chase amex.