Bummer
I know the feeling when a part comes out. I've had big parts that I'm getting paid for come out of my setups running the endmill across it making pretty tooth marks every 1/4"
because I'm usually climb milling.
On your piece; Could you cast it in some of that Bismuth alloy?
If you don't know what that is, it's a soft lead type metal that melts in hot water.