You can't send a message for 3 days? That's a really bullshit rule.
And about the site not having that manga, yeah, wow, I have yet to find a single anime that I've seen not listed here. It's really easy and only takes a minute to add a new one, though, over here:
http://myanimelist.net/addtolist.php
Just type it in, and on the right column, click the "add it to our manga database" link. You don't have to fill in the whole form if you don't want to, only the *'d fields, so it should only take a minute.
One thing that's probably frustrating you is the site's database lag. When you do anything on this site (like adding an entry to your manga list, or editing a score), usually it doesn't actually "register" the change on their database until 5 to 15 minutes later. I know, it's horrible, but once you get used to it, it's not so bad. But definitely, as you're doing the whole "initial setup" thing now, it will be a pain.
I've yet to find another anime site that does the things that MyAnimeList does though, like customized lists, thousands of ratings and plenty of reviews for anime, the ability to sort through all the anime and manga in the site's database through any criteria (e.g. sorting by score), a section on each anime page that states who the best fansubbers are for that anime, a good recommendation system, a page that concisely compares the anime you've seen with anyone else's (via the "All Shared" link) to see if this person's interests matches yours, plenty of statistics, etc. The only con is the database problem, but it really is an annoyingly huge con, so I hope they get it fixed soon, but it's been present for almost a year now.
Hope everything works out.
