A wrongly accused former sub postmistress in Co Tyrone has demanded accountability and an apology from the Post Office.
Deirdre Connolly described losing 12 years of her life after being falsely accused by the Post Office of a missing £16,000 due to a faulty IT system.
Ms Connolly described the devastating impact the false claims had on both her and her loved ones.
She has described being ‘interrogated’ by Post Office officials and at one point asked if she was stealing to give money to paramilitaries.
The Horizon system, introduced in 1999, saw thousands of users suffer unexplained losses which they say they were expected to "make good" on.
It led to more than 700 sub-postmasters and postmistresses across the UK being wrongly accused of theft, fraud and false accounting due to a flaw in the computer system.
Scores of workers were suspended, lost contracts and were wrongly prosecuted and/or convicted.
The Post Office Horizon IT inquiry, which has been sitting across the UK, began in Belfast on Wednesday and heard from two former postmistresses implicated in the scandal.
Inquiry chairman Sir Wyn Williams said he was very pleased to be in Belfast, and particularly welcomed those in the public gallery.
He described having been to London, Cardiff, Leeds and Glasgow before coming to Belfast to explore the impact the scandal had on people's lives.
It is set to continue at the Clayton Hotel on Thursday.
Ms Connolly was the first witness to give evidence to the inquiry sitting in Belfast.
She described how excited she had been to take over a post office and shop in Killeter, a rural village close to the Irish border in 2006.
Ms Connolly later agreed to take over two outreach sites in 2009 which the previous postmaster had given up over concerns at threats of 'tiger kidnappings', where a family is held hostage by criminals demanding money for their release.
She told the inquiry that while it was a challenge, people in those remote areas needed their pensions like anyone else.
However, she said she received little support from Post Office, and a supplied panic button did not work due to a lack of signal in the area.
On 2 June 2010 she said an official from the Post Office arrived to do an audit. He claimed there was a £16,000 discrepancy, telling her she was suspended.
Ms Connolly told the inquiry she was left "totally shocked ... just didn't understand what was happening".
The following week, she said the auditor said he had found £1,000 in notes in the safe so the discrepancy was reduced to £15,000.
She went through two meetings, which she described as "interrogations", which included her being asked if she had taken the money for the paramilitaries.
Ms Connolly said she and her husband asked their families for help and paid the Post Office over £15,000.
They had to remortgage their house and also went bankrupt in 2013 after people stopped coming into their shop.
In May 2013, Ms Connolly said she was diagnosed with epilepsy due to the stress.
"I didn't go out of the house for three years, when I did go out, I would cross the street if I saw anyone I knew from the area," she said.
"I was stuck in the house, only company I had was the dog Toby and he seemed to get me through it.
"My husband had to go through it all on his own in Killeter, people talking behind our backs, he was my rock, he's got high blood pressure now.
"My mental health will never be the same again."
Ms Connolly said a lot of people have not come forward due to the stigma, adding she hopes speaking out will encourage them to speak themselves.
"For me, I want accountability, A lot of people in senior positions within Post Office and government knew what was happening and didn't stop it," she said.
"We need to know who knew what and when. I'm hoping Sir Wynn will be able to get those answers."
She said the compensation issue also needs addressing urgently, adding no final compensation has been paid to any of the sub postmasters who had their convictions overturned.
"The Post Office ruined my life physically and mentally".
Sinn Fein Stormont leader Michelle O'Neill met the witnesses before proceedings started.
"I am here today to support these fine women, these women who have been wrongly accused of taking money from the Post Office in the past, these women who have suffered a huge miscarriage of justice, these women who are here today to reclaim their voice and their reputation," she said.
"These women have been wronged on every level and it's not just about an economic impact or a loss of finances or their business, it's about the loss of their reputation, it's been about the trauma they have experienced every day since these accusations happened, for some cases going back many many years.
"It's been a massive miscarriage of justice and I am grateful to stand here with these fine women to be able to say they are going to have the opportunity to put right what has been wrong and everything that has been said wrong about them. This is their day,"