What is wrong with the mail delivery system in The Crying of Lot 49?

In The Crying of Lot 49, the mail delivery system is the backdrop for a worldwide conspiracy. The mail delivering system is so useless that the owners end up sending weekly letters just to keep things operating and appearing to be effective. And in a satirical note, the post system is called W.A.S.T.E. (we await silently Trisero's Empire).