How do I get Turbo Tax to correct an error that they made on my tax reurn?

"Turbo Tax filed s refund from  2018 Federal Tax to the 2019 Federal Tax."

Sorry but that does not make any sense.  Please explain what you mean.  What refund do you think TurboTax "filed"?  Only a user enters information to a tax return.  Did you look your return over before you filed it?  TurboTax cannot correct your error.  If you made an error you are the only one who can access your own account and/or return and prepare an amended return.  

Or is what you are referring to an awkward way of saying you used 2019 software online to prepare and file a 2018 return?  Online is only for 2019--no other year.  Is that what happened?

Did you receive a letter from the IRS?  Talk to someone at the IRS?  TurboTax never knows when or if the IRS changes something on your tax return after you file it.

No one can call you from the user forum.  If you want customer support you can contact them during the week.

To call TurboTax customer support

https://ttlc.intuit.com/questions/1899263-what-is-the-turbotax-phone-number

They are available from 5 a.m. to 5 p.m. Pacific time  Monday-Friday

The only place a 2018 federal tax refund can be entered on a 2019 tax return is if you entered the 2018 federal tax refund to be applied to the 2019 federal taxes.  That amount is on Schedule 3 Line 8 and flows to the Form 1040 Line 18d.

A prior year federal tax refund cannot be entered as income on a current year federal tax return.

TurboTax support is open from 5am to 5pm Pacific time, Monday thru Friday

Use this website to contact TurboTax support during business hours - https://support.turbotax.intuit.com/contact/
Support can also be reached by messaging them on these pages https://www.facebook.com/turbotax/ and https://twitter.com/TeamTurboTax

Did your 2018 Refund show up on your 2019 return as an Estimated payment?  On schedule 3 line 8?  Did you receive your 2018 refund?