That's frustrating. One way to maybe get around that in the future is to add a white box over the text, then type the text again over it, or just screenshot the image only, and use the Spacing feature to make a space to type the text. If you add captions to it, it's less likely it will unfeature. I really think the mods are too strict about trying to make imgflip's content "unique" because that's an artificial standard that makes it hard for us who are just trying to make memes. Being unique isn't what makes a good meme, anyway.
Also, if you want to let the mods know it was yours, maybe use the Feedback button (on the side). I don't know if they will see your comment here or not. Sorry for the long comment.