I filed an extension but the government said they didn't receive it. Where can I find that document?

[xmasbaby0]

https://ttlc.intuit.com/community/printing/help/how-do-i-print-my-4868-extension-form-after-e-filing...

[Critter-3]

Good luck with that ... if they did not record the extension timely simply printing one off now will do you no good.  What you need it the email saying it was accepted  or  look in the tax history for the date it was filed.

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.