I don't understand why I'm rejected.
I've fulfilled all the requirements..
You equate fulfilling requirements with being selected. That is the problem.
If you have been around a little longer you will know that eligibility DOES NOT equal selection, whether it be for this job or any other job. If you fulfill the requirements for taking part in a lottery (yes there are requirements), does it mean that you will surely win?
Anyone knows what number i can call for the appeal?
The reason for the computerised application process is so that they can weed out undesirable applications not worth further consideration. They get hundreds of such applications a month which are doomed to fail from the start. If they don't have the time or motivation to process your application further, do you think they have time to entertain your queries? They are not career counsellors.
It's just one of the many harsh facts of life. Move on.
Or if you can be bothered, read this thread AND other related threads to have more insight on the selection process and how to succeed the second time around. It can and DOES happen if you can be bothered to help yourself instead of just asking, "Why ah? Why ah? Why I rejected ah?".