I have been a victim of overbilling because of a lack of health insurance. There is a nonprofit organization that, because of a lack of funding, cannot get the word out; they have to rely on the people they assist. They helped me reduce my bill by about 90 percent. Their Web site is www.hospitalvictims.com.
If you are willing to let them help you and do a tiny bit of work, it is well worth the time and effort.