Certainly, you should leave feedback on Yelp and other sites that allow you to do so. Did they give you any paperwork at the time of consignment that outlined their obligations? Did it state who has the obligation in case of loss or damage? I think that the consignee should take excellent care of items that are new and expensive. That said, the law may provide otherwise - eg that the consignee is not responsible for damages to goods.
That said, in the case of expensive items like Hermes handbags, it would be best to specify that the item is not to be used and that if not sold it should be returned in the same condition as when left. The reputation of the consignment shop really is important. Thank you for letting us know that this shop did not take proper care of the bag.