Health Republic lived a short and difficult existence, squeezed by premiums that were low by design and cut off by Republicans in Congress from government subsidies promised along with the federal health care law .

Yet the collapse of her insurer, Health Republic Insurance of New York — the largest of 12 health care co-ops nationwide set to close this year — has left her and more than 200,000 others in a panic over medical coverage after their plan ceases on Nov. 30.

With a severe nerve condition that forced her out of a job, Ms. Jackson did not just qualify for a government-subsidized plan, but she also knew her way around the new system, having been trained as a volunteer “health care navigator” to help others sign up.

If anyone could manage to obtain treatment under the Affordable Care Act, it should have been Liz Jackson.

Times readers learned nothing about the loss to providers. But David B. Caruso of The Associated Press writes:

The sudden collapse of the largest nonprofit insurance cooperative created by President Barack Obama's health care law is causing headaches in New York, especially for medical providers owed millions of dollars for treating the failed plan's patients.

More than 200,000 people insured through Health Republic Insurance of New York have until Monday to sign up with another company if they want to maintain coverage in December.

State regulators ordered the insurer to shut down at the end of the month because of severe financial problems. They are also investigating what they say were inaccurate financial filings by the company.

The closure — part of a wave of failures of the new co-ops nationwide — has been a big hassle for Health Republic policyholders, who have had to shop around quickly for alternative coverage.

The situation may be worse, though, for doctors, hospitals and other clinicians. They are legally obligated to continue treating Health Republic patients through the end of the month but have been given no assurances they will ever be paid for that care.

"I'm aware of at least two physicians who have gotten checks from Health Republic, and those checks have bounced," said Dr. Joseph Maldonado, president of the Medical Society of the State of New York.