Formal Multicolored party event dress - 10/12

Eliza J brand structured party frock with belt. Has super cute back cutout. Purchased from ModCloth. Worn 2 times to formal work parties, and received a million compliments. Tag says size 12 fits but I think its small and fits more like a size 10. Would fit a 12 (36C or less) or a busty 8. Knee length. Perfect condition. Formal engagement bridal event high end classy backless beautiful classic paint brush bright multi color button neck pockets high neck full skirt, watercolor,