You will have to contact the IRS and speak with an agent about the 2018 federal tax refund -

Call the IRS: 1-800-829-1040 hours 7 AM - 7 PM local time Monday-Friday
When calling the IRS do NOT choose the first option re: "Refund", or it will send you to an automated phone line.
So after first choosing your language, then do NOT choose Option 1 (refund info). Choose option 2 for "personal income tax" instead.
Then press 1 for "form, tax history, or payment".
Then press 3 "for all other questions."
Then press 2 "for all other questions."
- When it asks you to enter your SSN or EIN to access your account information, don't enter anything.
- After it asks twice, you will get another menu.

Press 2 for personal or individual tax questions.
Then press 4 for all other inquiries
It should then transfer you to an agent.

First, if you used Online TurboTax, make sure you successfully filed the 2018 return.

Log in to your account and at the Tax Home scroll down to the section "Your Tax Returns & Documents."  Expand that section and choose tax year 2018.   What term does it use for the 2018 return (Federal and also state, if applicable)--does it say accepted, rejected, printed, started, ready to mail, or what?