SHEIN black short sleeve square neckline tunic-size M

SHEIN black short sleeve tunic. Low square neckline. Zipper in the back. Bottom part of blouse is full and 2 tiers. Ties in the front below breasts. Size M. Armpit to armpit is 19 inches, length is 34 inches. Material is 100% polyester. Brand new never worn. Says it’s an L, but measurements say it’s a M.