the IRS has instructions on what to do if you receive an incorrect W-2 and the employer is uncooperative: https://www.irs.gov/faqs/irs-procedures/w-2-additional-incorrect-lost-non-receipt-omitted/w-2-additi...
If they are still your employer, I would wait for them to correct it. If you don't work there, any more, I would follow the IRS procedure.
