1040X - IRS asking for additional documentation

Greetings All, 

 

I have a turbotax premier product for tax year 2020. I prepared my 2020 returns (original and amendment) using Turbo premier software. I was unable to file the 1040X online and so I took a print out straight off Turbo and sent 1040X for 2020 to IRS. IRS has written back to me that they need additional documentation.  The two reasons I filed an amendment:

1. I claimed less CTC for my daughter by a mistake (regular Child tax credit and NOT additional). I incorrectly claimed $500 instead of $2000

2. The Economic stimulus I received for year 2020 was less than what  turbo calculated thro 1040X. ( I received $1,800 for a family of three, whereas turbo calculated that I should have received an additional $2,900).

As far as I know there is no specific documentation for the above and Turbo did not print out as well. Any help on how I can respond to IRS?