Chat is an option no phone call needed. Or you can book anything with those points like one night and it will default cancel the FW. Then just cancel that one night reservation. But I would bet they will allow for opting out online in the future.
Well, there's no fundamental reason it couldn't, but right now handling the fixed-week differential is a manual process. I suspect it is not worth spending the money to automate, because there just aren't that many FW owners (and there probably never will be).