Jumping through hoops

I was working one day a week, meeting with a job agency one week and Centrelink the other week. I handed payslips in to the job agency, where they were scanned and added to my file. I applied for jobs, I trialed at a few, during which I did not get paid. Three years later, and three years off payments, I get the debt letter. I was young, and very scared of what all this meant. Even though I knew I did everything right, I still had this large sum of money I was told I had stolen from Centrelink. When I called to ask about it, I was told I needed to provide payslips that I no longer had, and a separation certificate from a boss that called me horrible things when I quit her job. Needless to say I never got that from her, despite spending a year chasing her for it. I was also told I had to pay off the debt within the year, and was signed up to have a portion of pay deducted every fortnight and paid to Centrelink. I tried to fight it but getting the necessary paperwork was severely affecting my mental health, so I gave up. Just like they wanted me to. Until I moved house a few years later. In those years I had matured, learned to stand up for myself and my legal rights. Uploaded all the paperwork I did have and left the rest up to them. Called and appealed the debt again, this time not taking no for an answer, especially since I knew how many debts had previously been wiped or found to be wrong from the same time period. Had the debt amount reduced but not cleared. Still haven't received the money I paid that I didn't owe.