I filed in early January 2019 but didn't get 1099C forms from two creditors who had forgiven debt in 2018 until several weeks after filing. I totally forgot about including those amounts in my income. So I received the additional child tax credit payment, but my amount of income would reduce the amount I should have gotten.
I know I can file a 1040X form for 2018, which I am working on right now, but I cannot figure out what form to use to show how much money I need to pay back. Obviously, there is interest included as well. Do I file the 1040X and wait for the IRS to send me a tax bill? Is there an additional form I need to include? The only change is the two 1099C affecting the income, so I would only need to include those forms with the 1040X, correct?
Would another option be to file those 1099C forms with 2019 taxes when I file in 2020, adjusting my income then? If this is possible, it would save quite a bit of a headache, but I don't know if 1099C forms always have to match up with the year they were mailed out or the date the debt was cancelled.
