Vinted complaint: Incorrect sized item, unprofessional staff

Hi I would like to make a formal complaint, as an item that I’ve bought on Vinted has been sold to me under false description, the item (Vivienne Westwood jeans in navy) states it’s size 30 essentially waist 30 however it is a waist 28 at a push. I have sent photos of it measured to your support staff however they just ignored these and decided to complete the purchase and release funds to the seller before I even finished the conversation. The member of staff didn’t even leave their name under the message which is a normal procedure in any previous chats I’ve had in the past where the name is at the bottom. When asked why there is no name so I can file a complaint regarding that particular staff member I’ve been told it’s for security. So why do staff always leave their names apart from when there is an issue or they are at fault. The jeans in question were listed and have a label of 30 however I am or can attach photos that show another two pairs of jeans which are actually a size 30 next to the ones I bought to show the difference in size. I’m not sure if they’ve shrunk in wash but they are definitely not a size 30 as shown and proven by evidence attached. I would like to receive a refund for this and I can send these back to the seller as they are not the size that they say they are. I am awaiting your response.