Am I entitled for money if I was never remunerated for the expenses that are payable to me?

I have been separated from my previous employer for about 6 months now. They paid me my last paycheck; however, they never compensated me for all of my expenses that are owed to me. I have tried numerous attempts to reach out, but now they are unresponsive and have been for 6 months. They owe me close to $1000 and after being separated from the company. I think I have been more than patient. Am I missing something?