My stimulus submission was rejected on the grounds that there's an error on my tax return. But I had no return, as I didn't make enough to have one. What do I do?

I keep trying to fix it, but to no avail. And I can't find anyone to contact, unless I want to spend $30 on the upgraded software, which I can't afford to do. And when I try to make a new tax return, it tells me I need the upgrade because of certain income I had. But I had no income! Please help me!