My employer provided an incorrect W-2 form. After subtracting the various withholdings shown on the form (boxes 2, 4, 6, 14, 17 and 19) from the gross pay shown on the form (boxes 1, 3, 5, 16 and 18 show the same amount), I arrive at an amount that exceeds what I was actually paid. The employer did not respond to requests to correct it. What is the best way to handle this to make sure I do not pay taxes on income I did not receive?