I found my return product packet empty

By empty package I mean literally a polybag with a shipping label on it received in easy ship return order. How can it be even possible, what easy ship personnel was up to at time to collecting order. Events like this are really alarming for each and every seller. We sellers are working day and night for our business to grow and put lots of efforts to process every single order, after all this events like this are disheartening. I don't know whom to blame is it customers doing such things or delivery personnel, but something have to be done to stop this.