A new lawsuit claims Obamacare insurer Centene misled customers about how many doctors would accept their insurance, according to a published report.

The lawsuit filed Thursday in federal court by two customers alleges that they and others got skimpier coverage than what they signed up for, according to a report in Bloomberg. Centene has had success in Obamacare’s insurance exchanges, and has expanded their presence in the exchanges while other insurers flee due to financial losses.

The lawsuit, filed in the U.S. District Court for the Eastern District of Washington, charges that customers who bought Centene plans had a hard time finding doctors who would accept their insurance. It also said doctors listed by the insurer as health providers who would accept Centene insurance often did not, according to Bloomberg.

The lawsuit touches on a common criticism of Obamacare’s exchanges: that insurers provide narrow healthcare provider networks. A slimmer network with fewer doctors can help an insurer to control costs, a major issue for Obamacare insurers that have experienced a sicker-than-expected risk pool signing up on the exchanges.

A 2016 study published in Health Affairs found that in 2014, the year the exchanges went online, a plan with a narrow network had a monthly premium 6.7 percent less than a plan with a large network.

Centene is a major insurer in Obamacare’s exchanges on the individual market, which are used by people who don’t have insurance through a job or the government. The insurer announced last week that 1.4 million people signed up for its Obamacare plans.

Centene has expanded its Obamacare offerings this year, counter to other insurers who have fled the exchanges due to poor financial performance. The insurer did not return a request for comment on the lawsuit.