advice on what to do next…

* I am self employed and I use quickbooks self-employed to help me manage my quarterly payments*

 

I filed my 2019 taxes with turbo tax, now in 2021 as I’m going through a mortgage lender who needed transcripts for the past two years, I find out my 2019 is still processing, I gave a call to the IRS to find out what’s going on and they said due to covid to give it some more time, I waited 3 months and still nothing, so I called and called until finally someone told me a form was missing (something to do with a 1090A, health form) and they’ve been trying to reach out to me.

I got assigned a tax advocate to help. I sent in the document that the IRS needed.
a few weeks go by and comes to find out the REAL reason my 2019 taxes are still processing was an error on 2019 tax return (when I filed I put the total taxes I paid which were $3,991 and it stated in line 10 on 'additional taxes' total tax $4,572 (I sent in $581 with my return back in April 2020) and now I have a notice from the IRS stating that they fixed my 2019 taxes themselves June-July 2021 and I owe them $1259.07 + penalty and interest by September 2021.

 


I'm just confused on what I did wrong.

 

 

Will turbo tax help me figure out what happened here? The IRS is saying to contact who I filed with because they can only accept the payment or discuss setting up a payment plan