Now there's no point is wondering what to do about it. Once you've ensured that the guilty parties at the courier company have been properly dealt with (for eg, being assigned to the North Korea Prison Camp delivery round for the next two decades), it is time to turn your attention on your thieving neighbours.
I know. We once had a courier-delivered vacuum cleaner stolen from our front door step by neighbours, and they got dirty looks from me FOR AGES. However, there's a time for knowing glances, and a time for action, so we recommend these laugh-a-minute ideas:
Tempt your neighbours by sending them a box of cat poo "If undelivered, return to International Diamond Traders plc"
In the middle of the night, screw a big sign to their house saying "NICK GRIFFIN LIVES HERE", and they'll get all of Nick Griffin's mail (for eg, loads of cat poo)
Send a package to your neighbours marked "IMPORTANT and URGENT - Your new mobile phone is here! SHAKE WELL BEFORE OPENING". Sit back and laugh as they discover it's killer bees!!!
Spray their house in gravy and have it moved to the middle of a wildlife park in the middle of the night. When they wake up - LIONS EVERYWHERE!
Tape a message on the inside of the lid of their bin the night before collection day saying "All bin men are peados".
Subscribe them to The International Journal of Donkey Genitals, and insist that their delivery is NOT in a plain package
There. That'll learn them.