Hi Natasha, Sorry for cause you the inconvience!
This design in SKU we have been marked the Size on it, the size you ordered is 16cm+5cm( its for bracelet) 16cm size can not use for necklace, and we also write it on the product name: Necklace Bracelet Jewelry ( this design have both necklace and bracelet)
But We still apologize for cause you the confuse.