You mean you filed 2018 last year in 2019. Did you efile it?
Was your return Accepted? When you efile you get back 2 emails. The first email only confirms the transmission. The second email says if the IRS (or state) Accepted or Rejected your efile. Just paying the fee doesn't file the return. After you paid did you continue on to the very end and hit the big orange Transmit Returns Now button?
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?
if the IRS sent the 2018 return back, wasn't there a letter or notice explaining why? did you respond which would require whatever the IRS wanted and then send back the return to the letter in the notice + whatever else the IRS wanted? while you can go to the IRS website and see if they have a transcript of your 2018 return it is probably best to call them to find out what is the status of the return
First choose your language.
When asked for SSN do nothing it will ask twice
You should then be transferred to an agent, but there is likely to be a long wait.