UPDATE: the lost package has been retrieved: it was delivered at my housenumber in the P...street, where nobody lives. Somebody must have accepted the parcel and signed for it; then it was placed in front of that door. Two days later, another neighbour wondered why the parcel was left in front of that door, because nobody lives there. She took a good look at the address and saw it was a completely different address, i.e. mine. She took it to my address and rang my bell. We accepted it gladly. We've contacted the helpdesk of my new internet provider about the mistake that we have two new modems now.

Adri