I recently gave notice that I was quitting my job and my boss told me not to return to work. I left all of my hardware on my desk. The next day my boss texts me and says "X is missing." I know for a fact that I was not given this item, but my boss insists one was checked out to me.
My boss has now informed me that my final paycheck will be withheld until I return the item, but I don't actually have the item to return. I have made this fact clear to my boss but she does not seem to care: she will not pay me until she gets back this item I supposedly have. I don't have an employee contract and have never signed a legal document, let alone one regarding anything to do with hardware and hardware returns.
What is my next course of action?