The tax filing season has uncovered lingering wrinkles in the 2010 health-care law that have caused headaches for consumers who incorrectly estimated their income, didn’t use a government exchange to buy an insurance plan or changed coverage during the year.

Marta Chapman saw her anticipated $850 federal refund wiped out because she received too much in advance tax credits in 2014 to pay her insurance premiums under the Affordable Care Act. That prompted her to drop her plan for this year.

“I canceled because I was very upset. To me it was kind of a trick,” said the 48-year-old personal-care aide in Aztec, N.M. “If I knew that, I wouldn’t have got the insurance.”

Federal officials said they have been working hard to help people get used to the law’s system of financial help to pay health premiums, and will continue to try to make it easier for them. They said the Treasury Department had estimated the vast majority of people who got tax credits would still have some tax refund, on net.

“This is the first year that health insurance and taxes intersect,” said Aaron Albright, a spokesman for the Centers for Medicare and Medicaid Services. “Their tax credit may end up being bigger or smaller than expected, depending on what the person’s income was, but in every case, it is a tax credit from the federal government to lower the cost of their health care. We’re committed to listening and learning along the way so that we can improve.”

The law’s architects wanted the system to be fair, precise and well regulated. They tailored premium subsidies to the cost of insurance for people based on their age, local area and their household income for the year they have the insurance plan.