I honestly have nothing to say, i was in tears reading the first post. I know it ain't a nice thing but its some funny sh!t.
On a similar note there is a company in the states that specialise in delivering animal faeces to peoples front yards, any kind of animal too. Maybe try to contact these guys if you find the guy who sent it to you lives in the states, nothing says F you like a truck load of Moose sh!t in a mound covering his letterbox
Only in the US!! They really know how to take it to the next level