PORTLAND, Maine (AP)   A Maine health insurance cooperative is suing over the federal government’s decision to stop some reimbursements under the Affordable Care Act.

Community Health Options contends it’s owed $5.7 million in reimbursements that were supposed to be issued during the last three months of 2017.

The Portland Press Herald reports that the lawsuit focuses on a requirement that insurers provide reductions in insurance premiums for those who are eligible for tax credits in return for buying health insurance. The company said it provided those reductions because the Affordable Care Act requires the federal government to reimburse insurers for reductions.

The lawsuit describes the “statutory guarantee of reimbursement” as one of the health law’s linchpins.

Federal officials argue the payments had to be stopped because lawmakers hadn’t appropriated money for the program.