Vicki Gunvalson is so done with ex Brooks Ayers.

The "Real Housewives of Orange County" star took to Twitter on Wednesday to respond to fans asking questions about her on-again, off-again relationship with Ayers, after it was confirmed that he lied to her about receiving cancer treatments at the City of Hope National Medical Center in Los Angeles.

WATCH: EXCLUSIVE: Vicki Gunvalson Talks Brooks Ayers Red Flags on 'RHOC' Special

"City of Hope has not provided any cancer treatment to anyone by the name of David Brooks Ayers," Tami Dennis, Executive Director of Communications at City of Hope, told ET on Tuesday.

A Twitter user asked the 53-year-old reality star, "Why do u still talk to brooks, now that you know he lied to u and made you look like a fool?"

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Gunvalson responded, writing, "I don't talk to him nor will I ever speak to him again. This man is sick."

WATCH: Vicki Gunvalson on Brooks Ayers: 'I Got Duped!'

"I am not the one who was untruthful," another tweet from Gunvalson to a fan read. "I loved a man and believed him just the way they believe their spouses."

Ayers has been under fire recently after multiple "RHOC" castmates have been vocal about his cancer diagnosis, accusing him of faking the illness. Ayers has been denying the rumors that all of this has been an act, even providing fake documents displaying the City of Hope logo during a sit-down interview with E! News last week. The made-up bill, showing a balance of nearly $30,500, claimed that Ayers was receiving chemo therapy at the facility. 

WATCH: EXCLUSIVE: Vicki Gunvalson Spotted With New Man

Gunvalson has also been called out by her fellow reality stars. During a podcast interview with Heather Dubrow that aired earlier this month, she was put on the spot when asked about Ayers' cancer claims.

Dubrow candidly asked Gunvalson, "You didn't see meds in the medicine chest? Pills? Prescriptions…"

"I saw his pill boxes," Gunvalson responded. "I didn't see prescriptions."

"You mean you saw generic pill boxes?" Dubrow asked, hoping to clarify the response.

WATCH: EXCLUSIVE: Brooks Ayers Speaks Out on Fake Cancer Claims

Briana Culberson, Gunvalson's daughter, chimed in, revealing that her mom never actually saw cancer medications, just vitamins. "To this day, I definitely had red flags," Gunvalson admitted. "I do not have evidence that he does not have cancer. I don't have any evidence that he does."

ET caught up with Ayers in September, where he denied the rumors and insisted that his diagnosis was real.

"I have cancer," he told ET at the time. According to Ayers, he was diagnosed with Stage 3 Non-Hodgkin's lymphoma, a form of blood cancer, and was reportedly being treated by an oncologist. He also said that his "numbers were normalized" since he started taking supplements and doing IV therapy.

WATCH: Brooks Ayers Slams 'RHOC' Castmates Who Don't Believe He Has Cancer

"My lesion, my inflammations were gone. Gone!" Ayers claimed. "So I'm encouraged."

When asked about why his castmates would accuse him of lying about such a serious disease, he told ET he believed it was all to create intentional "drama."

"I think they do it to create drama -- manufactured drama and that's sad to me," he explained. "I've distanced myself in a lot of ways from it. It's useless drama that brings on stress that quite frankly no one needs and in particular my situation. I'm not running from anything."

WATCH: 'RHOC' Stars Respond to Brooks Ayers' Claims That They 'Manufacture Drama'

Gunvalson and Ayers officially broke up in August, after dating on and off since 2011. Their first split was in 2013, but Gunvalson got back together with Ayers in the fall of 2014, around the same time she had learned he supposedly had stage 3 cancer. During a "RHOC" reunion, Tamra Judge claimed that Gunvalson wanted to leave her then-husband, Donn Gunvalson, in 2007 to be with Ayers. Gunvalson, however, didn't split from her husband until 2010.