Vestiaire Collective bad experience

Vestiaire Collective Scamming Sellers, their customer service are insincere. Please share your experiences. I sold a Chanel skirt set up, their buyer cancelled after it was shipped, they then negotiated a lower than agreed price because they want to keep my items. https://us.vestiairecollective.com/profile/31930787/?sortBy=relevance&tab=items-for-sale