LifeStride Women's Carmen Ballet Flats - Medium & Wide Width

I bought these shoes in my usual size but they are too big! I see other commenters said they were too small but when I put my foot into them they felt loose and when I tried to walk they slipped off my heels and I could walk right out of them. Perhaps they are poorly sized and some are bigger and some smaller. I am ordering a half size smaller to see if that works.