What is POST doing?

I'm using the POST PickUp Import for the first time. I ordered from a site which delivered on thursday (I ordered on tuesday). I haven't gotten an update since last Friday on my delivery, I went to post yesterday and asked where my package is, and the man said it isn't here. He said it might happen that the PickUp Import is full, but in that case the delivery guy just gives it to the post office/building. I'm worried it will take too long to deliver or it won't deliver at all.