Buyer bought multiple items
After a week, buyer claims all items have a serious (but identical) issue, and demands a full refund.
Buyer is advised that his claim is impossible and is asked to provide a third party verification, stating all items have the exact same rare issue out of the box.
Buyer refuses, changes his story and claims the items work, but they are a different model than what was advertised.
Buyer is advised he needs to open a return.
Buyer opens return for the whole quantity of the order.
Buyer then writes saying he will return one item (1) and demands a full refund, or he will initiate a chargeback for the whole amount.
Buyer sends back a different, used, old model item with his personal information on it, and has the case closed against buyer.
Buyer leaves vindictive negative feedback, and initiates a chargeback.