After a cancer diagnosis and $20000 work of bills, what does someone with no health insurance do?

The person makes too much for Medicaid and was working. . .thought that insurance was going to be continued. . .insurance company was sending correspondence that the person was a customer. Now, they have gone back canceling coverage even before the diagnosis.

First of all - I would want to know why the coverage was canceled going back to before the diagnosis. There has to be a reason for doing so. If premiums were paid on the policy, then the only other valid reason for being able to retroactively cancel a policy would be if the person was not completely truthful on the insurance application.

If the premiums were paid and there was no misrepresenting medical history info on the application, then I would fight the cancellation of the policy.

If the policy was legitimately canceled, then I would unfortunately make payment arrangements as best as I could with my medical providers. I'd also investigate whether there were any charitable organizations or programs in my area that would help with my bills. Perhaps friends/family/church of the individual could throw a fundraiser (spaghetti dinner, etc.) to help raise money for medical expenses.

Get a lawyer, after John Edwards gets booted from the primary, get him to file a claim at the Insurance company.

Sorry to hear about this persons problem. Heatlh insurance and medical cost in this country has gotten seriousely out of control. It is shameful the insane greed the health care sector has been able to get away with.
As for your friend, they should worry about the bills if the opportunity presents itself. They should still be able to receive the same medical treatment, since it is a necessity. A public hospital can not turn someone away with a life threatening condition.

Well, usually they file for bankruptcy. Uninsured medical costs are the #1 reason for bankruptcy filings in the US.

Get the treatment now. Figure out how to pay for it later.