WASHINGTON (DC News Now) -- High rent prices in D.C. have long frustrated residents in the District. "When I was looking at prices, I said, 'Can you write down the prices of the units we saw?' And they said no because the prices change every day," said renter Patty Pierce. This week, the Department of Justice (DOJ) added six landlords to an existing anti-trust lawsuit against RealPage filed back in August, accusing them of colluding to keep rent prices high. RealPage runs an algorithm that recommends rental prices to landlords. The DOJ says landlords use that algorithm and privately share sensitive information with competitors to boost profits. US Justice Department accuses six major landlords of scheming to keep rents high "That type of collusion sounds pretty terrible. I don't think they should have that ability to actually communicate with each other ... because you know, they're all going to raise their prices a certain amount, and that's going to leave people out and push people away," said Corey Shadowitz. D.C. was the first jurisdiction to sue RealPage and more than a dozen landlords in November 2023. Attorney General Brian Schwalb said a high concentration of apartment buildings in the District are owned or managed by companies that use its software. "All these companies, no matter if it's buying a house or renting, they're artificially inflating the prices," Pierce said. According to the Washington Post, a single square mile in Navy Yard has 22 buildings that use RealPage to set rents. Greystar Real Estate Partners LLC manages six of those buildings and was added to the lawsuit. "They're pretty much kicking you out of the neighborhood, too. I don't think it's really appropriate either, especially since this neighborhood's really nice," Shadowitz said. In a statement, Greystar said the following: We are disappointed that the DOJ added us and other operators to their lawsuit against RealPage. Greystar has and will conduct its business with the utmost integrity. At no time did Greystar engage in any anti-competitive practices. We will vigorously defend ourselves in this lawsuit. Greystar Real Estate Partners LLC PREVIOUS COVERAGE: DC Attorney General sues 14 companies and RealPage in rent-price fixing scheme "You would hope that the rent price that you have - that you signed for originally - is kind of what you're going to be [paying] but a lot of places are increasing and that's unfair," said Sana Ajeena. On its website, RealPage said, "It's past time to stop scapegoating RealPage and now our customers for housing affordability problems when the root cause of high housing costs is the under-supply of housing which we have been saying from the beginning."    RealPage also said fewer than 10% of all rental housing units in the U.S. use its software to suggest rental prices, and recommendations are accepted less than half the time.