The buck stops....when you give up or shoot yourself.
I had a 6 year running battle with the IRS over a mistaken refund they made that they refuse to take back. Then a few years later when they discovered their mistake they wanted to charge me penalty and interest on it. It was a rather small amount really and my CPA begged me to just pay it but it was the principle of the whole thing. I finally showed my ass and got it resolved.