'RHOC' Alum Tammy Knickerbocker Says Missing Daughter Lindsey Is 'Okay': 'I Finally Heard from Her'

"We talked for about a half hour. She seemed like herself," RHOC alum Tammy Knickerbocker tells PEOPLE weeks after her daughter Lindsey went missing

Photo: Lindsey Knickerbocker/Facebook; Steven Henry/Getty

Tammy Knickerbocker has regained contact with her daughter Lindsey, who allegedly went missing several weeks ago.

The Real Housewives of Orange County alum, 59, tells PEOPLE that Jan. 9 was "the last time I heard her voice" until she "finally heard" from Lindsey on Saturday. The 34-year-old called her from Las Vegas to say she doesn't "want anyone to worry."

"She saw all the messages on social media and called me through Facebook Messenger saying, 'Mom, I'm okay. Leave me alone. Stop with all these messages. I don't want to talk to anyone,'" Tammy explains.

According to Tammy, she was able to narrow her search down to Las Vegas after finding out Lindsey was arrested there on New Year's Eve and spent a week in jail. She received a voicemail a few days later from a number she didn't recognize, and it was Lindsey "saying that she was on the Strip, and she needed money."

Tammy filed a missing person report and spent three days searching the city — where five to seven adults are reported missing each day, according to Las Vegas Metropolitan Police Department — before she eventually heard from her daughter.

"We talked for about a half hour," recalls Tammy. "She seemed like herself."

Tammy, who appeared on seasons 2-6 of RHOC, said that although her daughter wants to be left alone, she doesn't "know how to reconcile that," adding: "She's an adult, that's her choice — there's nothing I can do about it,"

"But she's still my daughter, and I can't write my daughter off. I want to help her in any way I can," says Tammy.

Lindsey's sister Megan Knickerbocker, 36, previously announced Wednesday on Facebook that her sister was "absolutely gone without a trace," days before Tammy shared a plea in her own post.

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"Worried about Lindsey, she is missing somewhere in Vegas, Henderson," Tammy wrote. "Any knowledge of her please contact me. Thank you."

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Megan has since updated her post to announce that "she has been found," explaining the situation and sharing a text correspondence with her mother.

"It's not the best outcome, but at least we know she's alive." wrote Megan. "Thank you for everyone who shared and helped find her, we couldn't have done it without you."