Hello,
I'm really in concern right now.
I filed Form-1040 in March by mailing paper to IRS but accidentally used non-filer tool in April, and so far I didn't receive my tax refund (they stopped processing paper returns) but I received my stimulus payment today (I'm qualified for the stimulus payment though, but still made the mistake that I used non-filer, which I shouldn't because I'm a resident alien). Any actions I should do in this situation? Thank you so much ahead.
Do I need to file 1040X if my 1040 is already mailed in March before I mistakenly used non-filer?
You probably received your stimulus payment based on your 2018 tax return. You need to send your 1040X 2019 as soon as you can.