I had the same problem!! You get in trouble if you don't file an extension. Despite three emails and two phone calls to my former employer, I still didn't have it until AFTER the filing deadline. How do I know how much taxes to pay?
Telling that person they can talk to their employer doesn't address the question.
We get questions from people in all sorts of situations. So I wasn't trying to be rude by not addressing the question flat out - I just want to make sure I understand the specific situation so I can give the best possible advice.
Here's what the IRS says about not having a W2 (you can see the whole page here https://www.irs.gov/newsroom/missing-your-w2-here-is-what-to-do):
If you receive the missing W-2 after filing your tax return and the information on the W-2 is different from what you reported using Form 4852, then you must correct your tax return. File Form 1040X, Amended U.S. Individual Income Tax Return to amend your tax return.
Forms and instructions are available at IRS.gov or by calling 800-TAX-FORM (800-829-3676).
Here's some other advice on other situations where people didn't have a W2: