I applied for a job recently. It was a federal job that took me months to apply and train for. After I gave my 2 week notice to my current employer, the federal organization pulled their job offer. 
Oh wow! what did you do?
I had to go back to my current company and ask for my job back. They had already posted my position, so it caused some issues, but they were glad to keep me. 
Thank goodness for that! 
I know. I felt lucky. And get this, a few days after they pulled my job offer, they called me back and said they had changed their minds!
So then what did you do?
I told them, professionally of course, that they could shove that job in their rump!
Yeah that's pretty crappy for sure!