I filed federal tax return electronically and turbo tax says it was accepted. IRS is saying that I never filed a return. Sent a letter on 12-2-19. Is there any way to prove the return was filed.

Please click here to view a thread with instructions for what to do if the IRS says they never received your return. This thread refers to year 2016 but it would be the same process for 2018. Feel free to respond to the thread if you need any more assistance.