I've had $50,000 worth of hospital bills that I blew off about 10 years ago. They call and write for awhile, then they sell it to a collections agency that can't prove why you owe that money, so just keep ignoring them and they'll eventually stop calling and you can write the credit reporting agencies and ask them to "provide full documentation regarding the circumstances surrounding the release of your credit report" - in which they most likely won't answer and will have to remove it off your credit report. Free healthcare!