Annoying behaviour

I live in a gated courtyard and the communicator thing from the gate to our flat is broken. I was expecting a delivery so I put a sticky next to the gate with my phone number on it so that the delivery guy could ring me and get in. Somebody removed it! Why? What on earth for? I would have removed it afterwards. Now I might have missed my package. It was my laptop, which I really really want. I just can’t understand why anyone would do such a thing. Not even kids out to annoy me would do that, it’s too subtly devious for them. Ack!