Ebay payment question?

That extra four digits is an extension of the U.S. zip code system. The postal system provides the extra digits to companies such as Ebay and others so that your shipment can be directed to the exact location of your address according to the zip code, rather than just a general area. It helps the post office sort the mail faster with fewer mistakes from trying to read actual addresses. They do this to verify that your address as you give it matches the zip codes in the postal service. Don't worry about this. You will get your package. It is a help to the post office to make sure you get your package as quickly as possible.