cell phone footage shows the complaint about an unsatisfactory milkshake served at a louisiana branch of burger king .
the discussion quickly turns ugly when the employee starts cursing before getting physical with the unhappy customer .
` you wan na get slapped ? ' the employee repeatedly asks the customer while standing next to her in an intimidating manner .
burger king has released a statement apologizing for the employee 's behavior and confirming that she has been fired as a consequence .