Vinted complaint: Return used mascara!

Hello. I paid for and received mascara from a seller who claimed it was brand new. On arrival the box came damaged, and before using the mascara on my lashes I always test on my hand beforehand to check its not been used. The mascara was dry, so I instantly messaged the seller (~10 mins after courier delivered the item) to advised of this and she agreed for me to return the item; at that point I had shared images which showed the damaged box it arrived in. Once she received the returned mascara, she then accused me of damaging the item, clearly something I would not do when wanting a full refund. Vinted have accused me of damaging the item and have told me I will not be eligible for the refund. I want my money back after false advertising from the seller but more so, disgustingly selling used makeup which can spread infection.