Ciao Vanessa,
AFCA has recently published your case (543442) and have reviewed it. I am surprised with their explanations. Seriously, they state that you were unable to close your positions, because it was a non-trading day, Sunday. Did AFCA take into account, that Australia is ahead of Europe. So, when it was still 17th of June in Europe (late Sunday evening), is was the morning of the 18th of June on the East coast of Australia. When the FX market opened it was 23:00:00 Sunday June 17, 2018 in Rome and 07:00:00 Monday June 18, 2018 in Sydney. And can see that, they tried to blame technical errors on your side of the transaction.
Have you tried to get ASIC involved? I assume you will not let IC Markets run away with your money?