UPS frequently mis-delivers my packages to a house with a similar number. Fortunately the neighbor who receives the package instead of me re-delivers it, but not until the next day.
I called UPS' "Customer Service" about the wrong deliveries in January, 2011 and she didn't care. She told me to check with my neighbors to see if they got the package by mistake. I'm not going to do UPS' job for them.
UPS needs to hire people who care about doing a good job and who are able to read and write. With all the people out of work these days, finding literate employees shouldn't be a problem.