how do they figure 27K?
This is a math problem first then a legal problem.
YOUR JOB is to gether your reciepts tax forms depsoit slips anything that shows income from this employer, and then look for ways you might have been overpaid
If there are none, then you wont have aproblem, but 27K is a lot, so it must be that something was approved by the manager who didnt have a clue about their job, about what is reimbursable and what is not.
They are looking for fraud, or money that was reimbursed to you that you just signed a reciept for such as charging the company for a first class hotel, but you stayed in a Motel 6 and pocket the difference.