Can I see tax return 4years ago

You can check to see if you have an online account and whether the status of a return prepared using TurboTax was "accepted", "rejected", or "ready to mail". If it says anything other than "accepted" then it was not filed. You cannot get PLUS right now in order to access the return, because the system will be in transition from 2018 to 2019 until sometime in December.

However, if the IRS is saying you did not pay tax due for that year, your only proof of payment is your own bank/credit card record.  TurboTax never knows whether you paid the IRS or how you paid, or when (if ever) you paid.

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

If you did not file your return, and you owed tax due, you are subject to failure to file penalties and interest on the amount owed.  The return would have to be printed, signed, and mailed to file it.