User blog comment:BenFugman/And they called it Trollpasta./@comment-4715955-20170515055154

"...I worked all day on a longer story..."

I'd bet money this is part of the problem. If you upload stories that you wrote in a day, unless they're microfiction or six-word stories, they're probably not up to quality standards. You should be spending at least a couple of weeks on every short story before submitting it anywhere. Most of the writing process is editing: it's not done when you type "the end", it's just starting.