Frankly, I don't know.
The Iceland Air website has a field to input how much you're asking for so I don't know what claim to make in the "Comments" field.
As for whether or not I was denied boarding, I was told my flight was cancelled, then I was put onto another flight. The replacement flight was 3 hours later (Amsterdam flight). But then I found out my initial flight wasn't actually cancelled. It boarded and took off before my very eyes. I was never given an explanation, so I assume I was denied boarding.
So I don't know which one to claim, the delay, or the boarding denial.