They owe me my last paycheck!!! - Floor Manager Zuma Restaurant Employee Review

I started working at Zuma Restauant in Miami, FL. on April 22nd 2014. I resigned on May 11, 2014. I had their training manuel and tshirt. I mailed them their items and have a receipt and proof that I mailed it to them and they said they didn't receive it. They are holding my last paycheck and will not give it to me and said thank you for my efforts. can you believe that. I emailed them a copy of the receipt. I want my last paycheck.