For voluntary changes it would always have required redemption space, so for that the refund is better than an FTV, since you can do that online. For the GUF, then yes that appears to have had the goal posts moved, but you would still need a flight to attach that to, and since this is redemption linked it's difficult to advise other than find a workable redemption. GUFs can be used on commercial bookings, and can be extended if unused, but you're probably past the point now. Customer Relations / Loyalty may extend it as a gesture but I wouldn't count on it.