After you file

You did not mention how long ago you filed that 2019 return by mail.   That is an important piece of information.  The IRS is very backlogged and it is taking them a very long time to process mailed returns.  Did you use any sort of mailing service with tracking so you know it was received--like certified mail, UPS, etc.?

Was the IRS refund site saying that your return was being processed?   In that case, only the IRS can tell you what happened.  TurboTax cannot find out.   No information is shared with TT after you file.  

To call the IRS:IRS:  800-829-1040  hours 7 AM - 7 PM local time Mon-Fri

Listen to each menu before making the selection.

First choose your language. Press 1 for English.

Then do NOT choose the first choice re: "Refund", or it will send you to an automated phone line.

Instead, press 2 for "personal income tax".

Then press 1 for "form, tax history, or payment".  

Then press 3 "for all other questions."

Then press 2 "for all other questions."  It should then transfer you to an agent.

TAX ADVOCATE

At the following IRS website, find the USA map and click on your state, and it will give you the number of your area's IRS Taxpayer Advocate.

http://www.irs.gov/uac/Contact-a-Local-Taxpayer-Advocate

Also see this article for more info on how the Taxpayer Advocate Service works::
http://www.irs.gov/taxtopics/tc104.html

No you do not put anything about your 2019 refund on your 2020 tax return.