i filed my 2018 return on this site yet the irs is tellling me they never recieved it?

Did they not get the tax return or maybe a tax due on it?  Did you efile?  Was it Accepted?  Maybe you didn't finish filing it or it Rejected.  When you log into your account you should also see the status and if it was Accepted or Rejected, Started, Printed, Ready to Mail, etc.  what does it say?

Then when you efile you get back 2 emails.  The first email only confirms the transmission.  The second email says if the IRS (or state) Accepte.d or Rejected your efile.  Check back though your emails if you have them.

How to access prior online returns

https://ttlc.intuit.com/community/prior-year-return/help/how-do-i-access-my-prior-year-return/01/27010

You have to log in to the same account.   You need to start entering some basic Personal Info in 2022 for the side menu to open up. Just continue a little ways into 2022.

In the PDF of your TurboTax return, the last page of the federal return should be an "electronic postmark" that shows your name, Social Security number, the date and time that you e-filed the return, and the date that the IRS accepted it.