"She's witty, she's fun, she has a big heart for people she loves, but I think Lisa is ... she's phony," Richards, 50, said. "Sometimes I felt like she was my friend, and you know, I believed her, but in a heartbeat she changes."
She added, "That really hurt because I thought, 'Hold on a second, I've always supported you and always wanted the best for you.' Even if I had my suspicions, I never really kind of revealed anything."
Despite what Richards said about her, Vanderpump still supports her. "I see what's been going on since then," she said of her Housewives' co-star's recent woes. "She told us she's struggling."
As for whether she thinks Richards should return to the Bravo show, Vanderpump says that is not up to her.
"Whenever somebody is on the show, they're on the show for a reason, and sometime the dynamic changes, not everybody is happy with certain choices," she explained. "But there's been a lot being said about me having the power to eliminate cast members. We don't get that power."
Vanderpump recalled her rough patch on the series. "I've done 170 episodes of reality television with Vanderpump Rules and Housewives. I've had a couple of really horrible, sh*ty experiences that I've never experienced in my life," she said. "The other 160 something have been amazing."
The 54-year-old reality star tells ET that she has not spoken to Richards, but says "she probably has a lot of support from her family."