Just Cavalli V-Neck Long Black Evening Dress Stretchy Size S/M

Just Cavalli V-Neck Long Evening Dress Very stretchy, slinky feel Purchased on The Real Real final sale, but unfortunately is too big for me :( The Real Real listed this as a size XS, but I would say it is more S/M (will post measurements tomorrow). No size tag on garment. Satin panels along torso and on the sides running down the skirt portion (see pics) Zip back Fabric: 90% Viscose, 10% Elastane; Combo 96% Polyester, 4% Elasthane