When she was 33, Sandra walked away from her twin sister to pursue a drug addiction.
Having already left her partner and daughter in Tasmania, Sandra returned home to Adelaide where she found out she was pregnant.
Unable to care for her second child, the allure of methamphetamine was too strong and so Sandra left her young daughter with her own mum — and disappeared for 13 years. Sandra's world had turned upside down, her drug addiction had taken over her life and her twin sister Tanya had no place in it.
"We were pretty close as kids," Sandra told news.com.au of her relationship with Tanya, who both appear in an episode of Insight on Australia's SBS network.
"When I was 22, I moved to Tasmania with my then partner. So Tanya and I went our separate ways then, as she also met a man and started a family. But while we had separation between us, we were still talking.
"But after my family broke down in Tasmania, that lead to a breakdown with myself. I walked away from my family, and returned back to South Australia in the year 2000. But I'd come back with a drug addiction."
Sandra said upon returning to Adelaide she had another daughter, but got herself "very deeply" involved with drugs, which resulted in her pulling away from everybody around her.
"I didn't want to see anybody, so I told the police that I was all right, but didn't want to contact her."
Tanya said her attempt at contacting Sandra through police had failed, and she feared she'd lost her twin sister for good.
"Sandra had become a different person, that's what happens on horrible drugs," Tanya told news.com.au.
"I thought something bad had happened to Sandra. My head kept saying something was wrong, but my heart was saying she was doing OK.
"I just wanted her to know that we weren't angry with her and we didn't hate her. But the more drugs she took, the more guilt she felt and that's when she lost herself."
After more than a decade passed, Tanya contacted the Salvation Army who sent an email to Sandra with a handwritten letter attached. Tanya hoped her emotional note would be enough for the pair to reconnect.
"I got contacted by the Salvos in 2016, and I had a depression and anxiety breakdown from it," Sandra explained.
"Once I opened up to the doctor [about mental health], I then opened the letter and rung the lady [from the Salvos] who sent it to me.
"I wanted to change my life ... but I'd never reached out to my family. There was just too much guilt and shame.
"One day, I called Nicola from the Salvation Army. When I met with her, we called Tanya. She was only 15 minutes away from where I was, so I went and saw her and have seen her every day since."
Tanya, who is a mum to five children and lives in Adelaide near Sandra, said the pair — both 45 — are stronger than they've ever been. And despite losing 13 years not speaking, they refuse to let history influence their future together.