First - contact your seller and explain the problem. If he has not yet shipped he can fix it immediately. But most sellers ship within two days so act fast.
If it is already shipped.....
Hmm - your postal worker probably picks up his loads at the local Post Office. Go there and explain your problem to the counter clerk. She may redirect you to a postal outlet (in a store) but this is unlikely.
Ask the clerk to alert the delivery guy. Sometimes these are contract workers, and not real posties.
If a parcel is undeliverable, for example, if there is an incomplete address, the Post Office will look for other clues. For example, if your parcel happened to be in the same delivery bag as your hydro bill, there may be no problem. Or the deliveryman may return it to the postal outlet where it will wait for you for a few days. So go and talk to them as soon as possible. Make sure the information is written down, because there is a lot of part time staff working those counters.
