Casing pipe stuck in borewell

I have a bore well which is 730 feet deep and since there is lot of slush, I get it cleaned once in two years. I have two 20 feet metal casing pipes installed. This time the lorry person while removing the rod, some how pulled the bottom casing pipe and it crumbled and got stuck at 18 feet. The lorry person said that he could do anything, and he wouldn't even be able to re-bore through the metal. How can I get this casing removed and install a new one? I'm with out water for almost 3 days.