@sashajh 

You are asking people on the internet that know nothing more than you can find out if you use the IRS resources. For Social Security Number issues, you would use the Social Security web resources.

The only thing we know, that you can also find out, is that this is an Advance on a 2020 income tax year event that would be filed when you work on your 2020 1040 form. If you don't qualify for the advance, I recommend you wait for the Tax Year and file the forms and that is when you will learn further as to how they put the legal code into regulations for the tax year.

No one here works for the IRS and no one here can tell you more than this. Sorry you find yourself in this situation, of course.