Maurice Lilio used to be an employee of Australia Post until he decided that stealing mail was more lucrative than sorting it.
Lilio was caught on camera slipping mail into his sleeves.
Two weeks ago, Lilio was found guilty on four charges of mail theft.More stories from Today Tonight
"That was once and it was by accident. I don't know if you've ever had your car keys or your cigarettes in your hand and you've put your cardigan on and you carry them through. I admit, it looks bad," Lilio said.
"An injustice has been done. There's no doubt about that, I feel absolutely shocked that I've been called a thief because I haven't stolen an apple in my life."
Lilio claims the courts got it wrong. "I don't want to go to jail for something I haven't done," he said.
Australia Post have been keeping a close eye on Lilio. When he left the building, Lilio was pounced on by police and caught with letters in his possession - none of them were addressed to him.
One of Lilio's victims had her identity stolen. It was used to access her bank account and she lost $15,000.
Australia Post handles 6.5 million letters a day in a sorting facility in Victoria. It is larger than the MCG and the challenge is to keep the mail safe and the crooks out.
Australia Post's Jane McMillan insists Lilio is an isolated example and all the mail are safe.
The organisation employs 33,000 people and processes more than 96 million pieces of mail annually. There are less than 50 complaints a year referred to the authorities.
"If you're doing the wrong thing at Australia Post, we have a number of measures that we put in place. We have CCTV in 4500 outlets. We have a whistle-blower program and we test the system quite regularly. That might include sending valuables through the post that are tagged. We can monitor whether they arrive safely at their intended destination or whether they have gone missing and we can track them," McMillan said.
Head of Queensland's fraud squad Superintendent Detective Brian Hay says criminal syndicates don't have to infiltrate Australia Post to steal identities. It can be as simple as raiding letterboxes to get that information.
"What is concerning is that the biggest threat to many organisations is the internal threat," Hay said.
Credit cards worth $26 million are stolen every year with much of it related to mail theft. Personal details such as your address, tax file number and date of birth can give criminals the building blocks to steal your identity.
Violetta is a victim of mail theft. Her credit card limit was raised from $500 to $2000 and spent without her knowing.
Violetta discovered the thieves were also taking out loans in her name - ruining her credit record.
"I can't even go and get a loan for the car," Violetta said.
While Lilio was working at Australia Post, he received a message on his phone that read "please look out for tax return checks".
The magistrate found it was most likely the mail Lilio stole was based on instructions received on his phone from a network of contacts.
"They haven't got any proof," Lilio said.