The only way in which you could have possibly been entitled to a refund is if A or P inventory were opened up. In that case, you could probably have technically tried to get the difference in fare. However, it is likely that only F inventory remained open, which costs the same on the route regardless of what ticket you had. Also, you always talk about flying in F on these negotiated fares, how do you know they aren't better than even the discount F/J fares given to the public?