Big mistake could have been a disaster

So I ordered a Wireless router along with the 80GB data bundle, when the delivery guy dropped off my item I questioned why I am only receiving a Sim card and not the device, he then said its probably because the device will be sent later.

But guess what, it seems it was not the case. I got a call from Cell C (luckily) and the consultant did a check up, and she noticed that the wrong item was sent to me.

How did this happen??? Now I have to wait until thursday and keep a sim card safe because of someone else's amateur mistake?