My job owes me money but won't pay?

My job owes me close to $400 so far, but I'm expecting another paycheck tomorrow. If that one doesn't show up, then they owe me about $440. I've complained to them and they said they would pay me, but they still haven't. What can I do?? I live alone and have bills to bay. I've got an electric bill and internet bill due in 2 weeks, plus I'm running out of food. They haven't paid me in over a month. I'm a freelance employee, if that makes a difference. But I still deserve money for the work I've done!