The leader of this company was also notoriously cagey. Several people never received their final few paychecks and she refused to answer any of their texts/calls.
The business is required to issue a w-2 by January 31. If you don't receive it by February 15, you can file with a "substitute W-2" form using your pay stubs for the information. However, this may delay your refund because the IRS wants to match the income and withholding that you claim to the records from the employer to prevent fraud. If the employer delays or never sends in their own records, that will likely delay your refund. It would be better to wait longer and get the official W-2, even if you have to call the owner and complain.
You can also file a complaint with the state labor department if the owner does not send the W-2.
You should always attempt to get your Form W-2, Form W-2c, or
Form 1099-R (original or corrected) from your employer or payer before
contacting the IRS or filing Form 4852. If you don’t receive the missing
or corrected form from your employer or payer by the end of February,
you may call the IRS at 800-829-1040 for assistance. You must provide
your name, address (including ZIP code), phone number, social security
number, and dates of employment. You must also provide your
employer’s or payer’s name, address (including ZIP code), and phone
number. The IRS will contact your employer or payer and request the
missing form.
https://www.irs.gov/pub/irs-pdf/f4852.pdf
https://www.irs.gov/newsroom/what-if-my-employer-goes-out-of-business-or-into-bankruptcy