Has happened to me as well.
I work from home and have had more than one occassion when they've left a note which indicated I wasn't home when in fact they never approached the door. I live in a subdivision that has a total of 12 houses within it. There is another house that has the same house number as ours but of course our street address is different. I'd hate to even guess how many times some pieces of our mail was delivered to that house and sometimes we get a piece of their mail. It is really sad that they raise the postage prices all the time yet the service gets worse and worse.