Earnings overstatement on w-2

There is a procedure to follow if you received an incorrect W-2 and have been unable to get your employer to correct it.  According to the IRS FAQ:  W-2 - Additional, Incorrect, Lost, Non-Receipt, Omitted

If by the end of February, your Form W-2, Wage and Tax Statement has not been corrected by your employer after you attempted to have your employer or payer issue a corrected form, you can request that an IRS representative initiate a Form W-2 complaint. Call the IRS toll free at 800-829-1040 or make an appointment to visit an IRS Taxpayer Assistance Center (TAC). 

• The IRS will send your employer a letter requesting that they furnish you a corrected Form W-2 within ten days.
• The IRS will send you a letter with instructions and Form 4852, Substitute for Form W-2, Wage and Tax Statement, or Form 1099-R, Distributions from Pensions, Annuities, Retirement or Profit-Sharing Plans, IRAs, Insurance Contracts, etc. You can use the Form 4852 in the event that your employer doesn't provide you with the corrected Form W-2 in time to file your tax return.