I had an accident 2 years ago - other driver drove into the back of my car when I was totally stationary at a giveway, so 100% their fault but of course no witnesses and they made up a *** and bull story which eventually led to me having to settle 50-50

That was bad enough but I now learn they are also making a big claim for uninsured losses as well so looks like I am going to be seriously out of pocket too

What should I do, and how is this 'uninsured' part allowed to happen??