I'm sure there is a fix for it, however, I've never had to do it and therefore can't really offer any sound advice.
I am surprised that the nut broke...! Was it so tight that you had to force it?
The only time I've ever had to use the ratchet was when I extended the jack just a little too much and had to free it with a very slight turn of the nut. Hope someone on here can help you out.