If you were overpaid for any reason, the employer can seek the money back: the law is very clear that a mistake does not let you keep money to which you are not otherwise entitled.They can't actually withhold your paycheck without your consent or agreement--the law is also clear about that. The proper way to recover money from you is to sue you for the overpayment. You could potentially sue your employer for you paycheck, if they illegal withhold it. They will then sue or countersue you for the money you owe them. It may be best to allow them retain the money and apply against the overpayment, to avoid excessive and unnecessary litigation.