An 8879 is only used by PAID tax preparers ... the TT program doesn't have it. Do you still have the email acceptance notice ?
Your return's electronic filing status history records all
e-filing activity related to the return, including the Electronic Postmark. You
can print it out if needed.
TurboTax Online
https://shop.turbotax.intuit.com/efile/efile_status_lookup.jsp --
enter the Social Security number of the first taxpayer on the return and the
ZIP code to retrieve your filing status history.
TurboTax CD/Download software
(Windows) From the TurboTax File menu, select Electronic Filing > Show
Electronic Filing Status History.
(Mac) From the TurboTax File menu, select Check E-Filing Status.
I sure you can legally refuse your company's request for your tax return or any part thereof. what makes me very suspicious is their asking for a form that would only be used by paid preparers. if you didn't use any software and mailed in your return, what could you provide them to prove you filed.
they should have all the info they need your W-2 and their books and records. say you paid your health insurance personally but didn't itemize. the only thing that would be left is your insurance invoices and checks.
personally I consider what they're asking to be an invasion of privacy. note I am not a lawyer. .