I booked a fully flexible C class WBC ticket on the KLM website (LCY-JFK) but am now unable to use it. The conditions seem to indicate that the ticket is fully refundable (that was the reason I chose it as there was always a chance I needed to cancel).

Here's a few questions, I've looked around and can't find any recent info on this, perhaps someone here has some experience in this:

Thanks for your help