Uh oh--are you sure you filed? What does it say in your 2016 account? Does it say "accepted" "rejected" or "ready to mail"? Does the IRS say you did not PAY your tax due for 2016? Do you have any bank/credit card records to prove that you paid?
Do you know how to find your account?
Many people have multiple TT accounts and forget how to access them. Log out of the account you are in now.
Account recovery
https://myturbotax.intuit.com/account-recovery/
https://ttlc.intuit.com/questions/1901535-forgot-your-turbotax-online-user-id-or-password
Or did you use the desktop version of TurboTax? If so, the files are on your own hard drive or any backup device you used like a flash drive.
https://ttlc.intuit.com/questions/1901486-how-many-turbotax-accounts-do-i-have
https://ttlc.intuit.com/questions/1901535
https://ttlc.intuit.com/questions/1901659-find-your-tax-data-file-in-mac
https://ttlc.intuit.com/questions/1900721-find-your-tax-data-file-tax-file-in-windows
I filed 2016 taxes, irs doesn't have their copy, how can I get a copy?