Rejected posts are always acknowledged, and you'll usually get a reason as well (don't post in HTML, don't post large attachments etc).
However:
1) If your messages are in a moderation queue (and they may well be as a new member) then depending upon time zones and which moderators are online etc, it may take half a day or so before the message is seen and moderated.
2) If you post via the gmane newsgroup then there is a delay before gmane passes the messages on to the list.
3) If the list server is busy, or your ISP is busy there may be a delay before the message travels through the list and back to your mailbox, I've seen delays of up to 3 or 4 hours for my own messages to get back to me (via the list).
John.
Thanks very much for the response Mr. Maddock, I guess I'll have to keep looking for my problem. I was concerned when it seemed to be a day or two of silence. Since you didn't tell me to bog off I'll just keep hanging round and earwigging then. :) Apologies if gmail is sending HTML, I'll go look to turn that off.