The two policyholders have filed a lawsuit in federal court against Health Insurance Innovations, based in Tampa, Fla., accusing the company of misleading them about the kind of policy they were buying. They say they believed they were purchasing Affordable Care Act plans that include coverage guarantees. But they were sold much less comprehensive coverage that left them vulnerable to tens of thousands of dollars in unpaid medical bills, according to the lawsuit. Their complaints underscore problems with some types of cheaper health insurance alternatives that the Trump administration has expanded. Critics of the government’s decision, including the Association for Community Affiliated Plans and the National Alliance on Mental Illness, are also suing the Trump administration over relaxation of rules for these plans. “This isn’t real insurance,” said Jason Kellogg, one of the lawyers representing the individuals in the Florida case. They are seeking class-action status, estimating that as many as 500,000 people may have bought these policies.