Cashbuild - Salary complaint

I was supposed to work for the company for a week as casual.but I only worked 2days because they didn't give me a contract or tell me how much I was working for.at the end of the week I was not payed with other casuals that I worked with but they worked the full week .without being called I made an effort use my money to go to them they said I will be payed the following week which was month end ..and I have a contract that is filled with my information and the signature that Is not mine saying I was supposed to work from 7 to 6 which is 11 hours and earn 220 or twenty something per day..still today I havint got payed its been three weeks now ...anyone please help