Flight Centre Travel Group

I booked a package to queensland as a short 4 day stay and had a long and very clear conversation with Mikaela Brouwer at Flight Centre Berwick about needing to return home on the saturday as I was flying out on the sunday to japan
we discussed this at length and went through an itinery I didnt confirm the actual dates as I trusted by our conversation it was very clear on the dates and she understood very clearly on my need to return on the saturday so I could prepare to leave for japan.
so after briefly going through the itinery and signing off TRUSTING she had listened to my needs and booked everything correctly
1 week later when booking annual leave I find that she actually hadnt listened at all and had us returning to melbourne on the sunday which is the day I am leaving for japan.
I was stunned after such a specific conversation that she was able to make such a vital mistake and I put it down to not really listening to the customer. so upon questioning about this I was told either side was booked out so I cant change it and cant get a refund but can come back a day early and pay more to change my flights.

I find this as a first time I have dealt with your company both unbelievably incompetent and a really bad start to a business relationship
I dont accept her answers well you signed the itinery and I have lots of conversations so I dont remember yours when the whole trip was based around returning a day easrlier because of the japan trip.
I find this behavuor unconsionable and would like some kind of satisfactory resolve please