Legal Question in Business Law in Massachusetts

Technically it is a payment error and they will seek a return of the funds.

You have two choices: notify them of the error and get the matter sorted out so that your w-2 is correct at the end of the year or don't do anything and wait for them to find the error.

If they find the error, they will demand a return of all the money.

I would call the payroll dept and notify them that you no longer work there and work out the correction of the problem. If it is a payroll service, you could call them directly.

Good Luck