Are you trying to mail your items from a character on one server to a character on another server? Unfortunately, you can't actually do that. The only way to get items cross-server is by putting them in the inventory of a character you transfer (which again costs $25). So you probably mailed the items to someone on your old server who has the same name as your new server character. If they don't log in and take them, you'll get them back in your original character's mail in 30 days.

The good news is, there really shouldn't be anything on your original character that can't be easily replaced on your new-server character. Everything pre-level-20 is pretty small potatoes, relatively speaking. Whenever you start fresh on a new server, your first character has to build up from scratch.