She added she and Jackson had been close friends with Brent during filming, but he later "ghosted" the pair.
"I was heartbroken when he started ghosting us. Then I saw videos of him standing with people who were chanting, 'F**k Olivia', and I was enraged," she said, referring to the moment at on-screen rival Domenica Calarco's post-MAFS celebration.
"He never apologised for ghosting me or anything. He never reached out while MAFS was airing or after.
"He was our bestie while filming. He was at Jackson and mine's flat all the time. He nicknamed us 'mum and dad'. And the only time I've heard from him is some mean text me sent me about something that no one cares about."
In her Q&A Olivia also addressed questions about her recently launched OnlyFans account, which earned her $10,000 in her first 12 hours on the adult subscription site.
Olivia, who is currently travelling around Europe, admitted she had made a sex tape with Jackson, but nobody would ever see it.
“I was never ever, ever, ever going to let this story see the light of day, but it’s so funny,” she told fans.
“We filmed a sex tape before I left Aus, and it was a disaster.
“Yes, would consider doing a sex tape, did consider doing a sex tape, did the sex tape and it was a disaster. So that idea is going back in the drawer.”
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