COS PHONES At COS Phones, we are a large reverse logistics company for major US carriers. We move cases, accessories as well as an expansive variety of devices. We recapture the best value for returned and unsold mobile products, with no headaches for you. Carriers, manufacturers, insurance companies, and retailers worldwide trust us to move overstock quickly and reliably. Our infrastructure, processes, and relationships make reverse logistics the easiest part of your job. COS Phones purchases and sells whole overstock inventories of high and low-end mobile devices and accessories worldwide. The products may be unsold, obsolete, returns, or trade-ins.