When you filed for the stimulus you were telling the IRS that you would not be filing a 2019 return. Filing for the stimulus, as a non filer, is the same as filing a tax return. You should have filed your taxes to get your stimulus, because evidently you are a filer. Just call the IRS and explain to them that you filed for a non filer to get your stimulus, but now you have to file your taxes for 2019.
