Please take a look at the description of the MAL supporter here (https://myanimelist.net/membership).
And also read our MAL Supporter FAQ, as many common problems are already described there. If you cannot find your issue, then please click the "contact support" and fill out the form.
You can register for MAL Supporter only on the web.
If you could be a supporter, it would be a great help to us in running MAL!