Here’s what consumers have asked with answers from LilyWardrobe staff and previous consumers.
Hello! To be honest, I don't think you can. I'm currently stuck in the same situation as you and I've contacted them and they've offered me exchanges/store credits etc. I've had enough of it all (and they have also left me on read multiple times!). I used PayPal to pay for the goods and have contacted them to help dispute it. I may try contacting Fair Trading Australia (I live in Aus) to assist as well.
SCAM! Do not go anywhere near them. False advertising, poor quality, wrong sizing, not fabric as advertised (promised linen cotton got polyester) refunds non existant.