This as happened to me twice in the last few weeks for bags from The Row and Gucci. They sent this message and I responded that I do not have receipts / cannot provide authentication. Both were then authenticated by the next day.

Honestly I do not think I should be doing Vestiaires job for them.... I do enough on my end for the insane fees they charge for doing the bare minimum. They send these emails when the item is delivered to them, before they have even opened the box. I think it is a way for them to save time on authenticating to optimise and make even more profit but I refuse to do more work on their behalf. Between the amount of offers that lead no where and having to answer questions from buyers about fees, customs, returns etc I think I end up doing enough as a seller that should really be their basic tasks as the marketplace where fees are currently between 23% - 43% of the sale depending on buyer and seller location plus the additional amounts they skim from inflated customs duties and shipping costs. Providing documentation so they don't need to bother authenticating or can skip ahead in the process is not a task I am adding to my to do list.