INTERFACE TALENT DID NOT RETURN OUR MONEY East Brunswick New Jersey

We visited interface talent with our 11month old son on Sep 4th 2013. We were offered an appointment 1 week later. I came home and read all the issues this company had with other folks. So immediately according to their policy returned a signed registered mail requesting a refund. Their policy was to send a written registered mail in 3 days. We did it the next day. I still have the receipt copy. We had called them numerous times in 2014 and everytime a new representative would answer and give us a different story. They confirmed they had received our registered mail requesting a refund. They even gave us a check number and said we will get in a month. Nothing as of August 2015. I am the only person earning in my family and follow rules and am go fearing. $600 is a huge amount for us who live on a single paycheck. Please if you can help us get our money back it would be really helpful. The owner deserves to be punished  for cheating people like us. We go tired of calling and stopped. We never moved so there is no chance they mailed the check else where. They said they have outsourced the financing work to some other firm but we never heard from anyone. Please help. And for god sake avoid them forever.