Worked and didn't get paid salary that was due

I was a Christmas Casual at the then newly opened Typo at Gateway from late November till late December. I was overworked, worked 11 days straight without leave, once worked without a break. When it was time to get paid, my salary was short. I waited a month before they still paid me less than I was due. Two months later and I still wasn't paid my correct amount. It is now late April and I still haven't been paid my complete earnings. I have mailed the retaill operations manager countless times and my last two emails weren't responded to. It's been a month since he last responded. Disgusted by how they are able to treat workers in that way. Seems like slavery to me