Why cant Centerlink prove to me when they gave me this money?

on the 23rd of December I received the call from a collection company asking me for 15K and to my horror they wanted it straight away. I was not aware of the money owing or l would have paid it back.

I am a single healthy working mother and I did get sick in 2013 when a surgeon was doing day surgery for problems in my womb and they accidently put two cameras through my bowel and it was not picked up for 3 days in private hospital in central Melbourne, my friend ended up yelling at the nurses and they called the doctor who was discovered to be in hospital herself and the assistance surgeon was not aware of me still being in hospital. long and short of it was that l almost died twice and then they could not find an available surgeon to save my life in Melbourne at 5pm on a Thursday, they found someone and 4 operations later and they placed my into a coma for several days. another two operations and 6 weeks in hospital and 5 months at home learning to walk, go to the bathroom with fatigue issues and they gave me ammonia on the lungs. I received no compensation due to this accident because I signed the paperwork at the hospital.

So this is the only time that I have ever claimed since mother pension because I was recovering from all the operations and trying to keep my house with a mortgage.

I don't understand the Family Benefit A and B, some times I received $ 7dollars in my account and other times I receive $62.50 but these are made up figures because it always changes, I assumed that Centrelink have a formula that they work to and I have never understood it.
I am a contractor and when I did get work, I was paid for it but with all my strength and fatigue issues it was not consistent and I tried to call to highlight my income and after 40 - 50minutes, I often give up and hung up.

so I decided to write a letter to Centrelink in 2014 stating that I earn 100,000 a year even thought a did not because I did not want the money and I thought they would stop putting money into my account. I went to their offices for a few hours in Ringwood and they had received the letter but not applied the information to my file and therefore that was why they were still giving me the allowance. I informed them again that I earnt 100,000 so they would stop giving me money and it stopped by going to the office.

when I received the first call on the 23rd of December 2015, I gave them $500.000 dollars off my credit card because I did not have the $15K.

I did ask for background information but this call on the 23rd had already gone to the dept recovery company and they said they have no back up information. they wanted to take 200.00 dollars a month from my account and I had no say in the situation.
then I missed a few payments from my account because when they went to draw the money out, I did not have any there, this is my main only account. I was working for less money because I was not strong enough to do the job I did previously when I was not sick.

I went to the Centrelink office in Ringwood again and spent 3 hours there with no joy, they could not help me and said I had to call another department which I did and I was just transferred around the world. The amount of times I called and set aside a morning or afternoon, to call and resolve this situation with no joy.

Then my file was changed to another dept recovery company who were just as rude to me as the first one.
In 2015, I wrote a letter saying that I earnt over 140,000 a year which I did not but it was to try and prevent them from giving me any money. one day I received an amount of $1.87, really why oh my gosh.
So I have been continually calling trying to log onto the web sites and search for hours on end looking through all the options with no luck or a statement that is just general.
I was able to find some monthly statements but not indicating dates.
So I just paid the $200.00 every month from July 2016 until march 2017 and the stress has been amazing.

I lost my house because I could not keep up with all the payments and life, bills etc.

I didn't know how to solve this problem, I am by myself with no adults to talk too and its embarrassing how this could happen and I could not work out how.
In late 2016 I wrote another letter to centre link saying that I now earnt over 180,000 then hoping that they never give me any money because I did not want to pay it back.

Then I was able to get some statements of the owings which are from 2012, 2013, 2014, 2015 and they have changed me a dept recoverey fee applied on the 23rd of December 2015 of more then $ 1700.00 dollars but this is the date when I discovered that I owed the money. Therefore really my owings is $13,300, and this is the only the statements that I have worked out how to download, what other fees are being applied to the dept that I do not know about.

apparently I owed $700.00 dollars in 2012 and that year I received a tax return back of $3,000, so why did the ATO or Centrelink take that money out of my tax return or did they not know that I owed the money but why did they not tell me that I owed the money or do l.

also in 2013 when I was extremely sick I did have problems getting through to Centrelink and inform them of my income, so maybe I do owe this but again what ever I owed was not removed out of my tax return.

I know that they remove child support from peoples tax returns, so did they (Centrelink) find out that I owed the money in December 2015 for all the previous years owing.

I called two days ago the debt recovery company who I have now being paying to them for 9 months and asked for a statement because I wanted to confirm this second company has recorded the first 500 dollars received on the payments and they after some discussion said they do not do statements to us.
I informed them that anyone who has any kind of loan will get a monthly, 3 monthly or sometimes 6 monthly statement to indicate how they are traveling on their loan, they hung up on me.

So is that what you get with customer service, I called back and my case has magically been given to a supervisor and he indicated that it was very unusal to be provided with a statement. I also after reading some articles on line and in the newspaper that I could ask for an extension because I am currently experiencing hardship, they said they would give me 14 days which is nothing because the next payment comes out in 21days.

I am posting today an appeal document to Centrelink to try and have my case reviewed. Fingers crossed.