stole $400 from me, what should I do?

17D Ago
I received a $400 payment and "cashed it out" to USD in my wallet so I could transfer to my bank, but never received the USD in my account. It took 2 days for my BTC payment to be completed, but then never received the USD for it in my account. My account says my Sell Order to USD is 'EXPIRED' but my payment for the sell order is marked as complete? What should I do? ​