Black sleeveless top w/checkered flared black & white bottom. Sz Small runs big.

Rue 21 ultra trendy, extremely well-cut and extremely flattering sleeveless top w/checkered, flared black & white bottom. The shirt has never been worn for more than the few minutes it took to try it on. I’d lost a bunch of weight and I ordered this online and found it was much too big, but couldn’t return. The size is listed as Small, but my sister who’s a size 12 tried this on and it fit her perfectly (although she didn’t want to buy it off me since she had something similar). Has been sitting in an air-tight back for about 6 months. Smoke-free, pet-free home additionally. Happy to take offers. This is new without tags, 100% polyester.