Applications rejected

Hi,
I need other opinions. I send applications to Codecanyon, android applications, to use REST API for my web application.
But I get the answer like this "This item has a nice concept, but doesn’t feature the required functionality and features to be approved as a premium item."
You can see demos, here:
librarian
parent
student
teacher

Can someone help me and give me some feedback to they approve it. I don’t see where is the problem and like to make a wish come true to some customers who like to see and use android application.