Disabled (SSI) non-filer, have never filed, eligible for stimulus payments but rejected because I was wrongfully claimed as a dependent on another return by someone I don't know. Help!

Have been disabled since I was a teenager, only income is SSI so I have never filed
Am eligible for stimulus payments
My parents DO NOT FILE so it was not them who claimed me as a dependent
Was rejected with code IND-516-01 saying I'm being claimed on someone else's return.
I am nobody's dependent and haven't been for at least 10+ years!
Don't know what to do, don't know how long it will take to get this resolved, don't know if I'll receive the payments way down the road once this is all resolved, don't know how to prevent others from claiming me as a dependent in the future.
Called a ton of IRS hotlines for the past few weeks and nobody has any answers for me, if I even get ahold of a person at all
Only advice I was given was to fax form 14039 to the IRS. UPS store tried from open until close for 3 days in a row to send the form and copies of the rejections + my SS card + my ID to the fax # on the form and it never goes through.
The form says if you're mailing it to send it where you usually send your paper returns, BUT I HAVE NEVER FILED A RETURN.
I read something online saying they are storing a lot of their mail intake in storage for months before going through it because of the virus
My local irs office has been closed because of covid
When I try to talk to people at the stimulus hotline they tell me they can't help me because they can't ask me security questions because I've never filed.
There are no resolutions for my specific issue on the irs website.