Here's the problem. In order to ship a set top box to you, it has to be shipped, as in, someone needs to physically carry it to your home. Verizon uses UPS, arguably the most reliable shipping company in the world.
UPS doesn't deliver on Sundays, and they work minimally on Saturday. Even if they did work full hours on Saturday, depending on what time you actually called in, (Any reports after 3 PM are processed the next day), would have been delayed either way.
UPS is far more responsible than Verizon is due to any delay in shipping.