She signed onto HealthCare.gov and entered all his information: age, birthday, address.

"Everything is systematic. It wasn’t that difficult, really," she said. 

They picked a plan sold by Coventry because it covered services at Roper St. Francis, but they chose to drop the policy mid-year because their income changed and her husband, Mukundadura, no longer qualified for a federal discount. 

They were forced to pay back the insurance subsidy he'd received for nine months in 2015 because they had underestimated their household income. Later, the Pereras found out they owed an additional penalty because he was uninsured between September and December of that year. Then they were mandated to pay the federal government another $600 because Mukundadura remained uninsured throughout 2016.

"That’s like my internet bill for the whole year," Elizabeth, 33, said of the $600 fine. "You’re punishing people who are working hard to make ends meet."

When the Pereras, who live in Ladson, decided in December to enroll Mukundadura in a policy for 2017, they found their choices on HealthCare.gov were much more limited. Coventry was gone. Consumers' Choice shut down. Aetna cited higher-than-expected costs and decided to pull out.

At one point, five health insurance companies sold Obamacare policies to customers in this state. This year, BlueCross BlueShield of South Carolina is the only company left.  

In this regard, South Carolinians share something in common with Obamacare customers in Alabama, Alaska, Oklahoma and Wyoming — only one insurer sells Affordable Care Act plans in those states, too.

This is especially worrisome as Congress inches closer to dismantling the federal health care law. Insurance companies must decide by late June if they will sell HealthCare.gov plans in South Carolina next year.

If BlueCross BlueShield unexpectedly backs out of the marketplace, nearly 200,000 patients in this state who rely on that single company for coverage under the Affordable Care Act may find they are left without any options. 

Technically, these patients could buy a policy "off the exchange," but they could not use a federal subsidy to lower their costs and most of them couldn't afford to pay full-price. 

This worst-case scenario isn't very likely. Patti Embry-Tautenhan, a spokeswoman for the insurance company, said BlueCross BlueShield of South Carolina intends to sell plans through the federal marketplace next year "assuming there are no significant deviations in the rules."

The U.S. House of Representatives passed a version of the American Health Care Act in early May that was designed to reduce premiums, but, if signed into law, would likely make health insurance unattainable for millions of people. For this reason and others, the proposed bill will almost certainly change in the Senate, making it difficult for insurance companies to predict what rules they will be forced to comply with next year.

"Like everyone else, we continue to pay close attention to what’s happening in Congress," Embry-Tautenhan said, "which promises to be fluid for the foreseeable future."

Ray Farmer, the director of the S.C. Department of Insurance and a member of Gov. Henry McMaster's Cabinet, is most worried that Congress will nix the Affordable Care Act's "cost-sharing reductions," which President Donald Trump threatened in April to stop funding.

Those reductions make health insurance policies much more affordable for low-income people, and 90 percent of Obamacare customers in South Carolina qualify for at least some discount under this program.

"The cost-sharing reduction piece has got to be the No. 1 issue for us in South Carolina," Farmer said. "In my opinion, the market will implode if (Congress doesn't) fund the cost-sharing reductions and address it going forward.

Insurance companies must submit their proposed 2018 plans and rates to Farmer's agency by June 26. This year, he will allow them to file separate proposals and prices based on two scenarios: Either Congress continues to fund the cost-sharing reductions or they don't. He would not speculate if health insurance costs will increase next year.

"I expect BlueCross BlueShield of South Carolina to come in and make that filing. From what I’ve gathered so far, they’ll be writing in all counties just like they do this year," said Farmer, who doesn't anticipate other companies will step in next year. 

"Ideally, yes, we’d have a number of competitors, but I’m thankful for our one competitor that is in the marketplace today," he said.

South Carolina isn't the only state facing so much uncertainty. 

Humana announced in February it won't sell HealthCare.gov plans to customers in a broad swath of eastern Tennessee next year. The company's decision was especially problematic for customers in those 16 counties because Humana is currently the only company selling this type of insurance where they live.

On Tuesday, Blue Cross Blue Shield of Tennessee announced it will fill this coverage gap in 2018, but the company said it will price these policies accordingly "until stability can be achieved."

Customers in most of Iowa face the same potential problem. This year, three companies sell Affordable Care Act policies there, but all of them recently indicated they plan to pull out. 

Farmer, who attended a meeting earlier this month with other insurance commissioners in Washington, D.C., said his colleagues in other states are facing the same concerns.

"As you can expect, I’m mainly concerned about South Carolina," he said. 

Elizabeth Perera, like Farmer, agrees that Congress needs to fix the Affordable Care Act, but she doesn't want to see all of the law's provisions disappear.

She is particularly concerned lawmakers will scrap Obamacare's "essential health benefits," which require insurance companies to cover, among other things, maternity care.

"If we have kids, I expect my insurance to cover my maternity care," said Perera, who is insured through her employer's plan. "I will need it eventually."

For now, Perera said she and her husband are happy with his coverage. BlueCross BlueShield of South Carolina is a good company, she said, and many providers accept his insurance. 

"I work in a medical office. I understand insurance pretty well," she said. "That’s a pretty good option to have."