You purchased a brick. Your assumptions are correct.
The devices are so inexpensive, that it makes no sense to buy a used one. Users typically keep their devices until they break, and the ones for sale on eBay, Craigslist, etc. usually have some sort of hardware issue or were carrier-locked.
Do note that the 302 model is designed for service provider deployment and management; it's not a consumer device. You want the 202.