Call the IRS at 800-829-1040. They will contact the employer. For more information go to the following link on the IRS web site. (The IRS is still working during the government shutdown.)
If you don’t get a W-2 or your W-2 is wrong
If you end up needing to file Form 4852, you can prepare it in TurboTax and it will be included in your tax return. You do not have to use the Form 4852 that the IRS sends you.