Understanding Leave Policies
Leave is a privilege and not a right, at least to some extent. Therefore, you need to apply and get approval for it. Please check your company's standing orders, which will outline the process of application, approval, and rejection. If there is no specific process, then the normal commercial process is followed.
Steps to Take if Leave is Denied
If the company does not grant your leave, then you should report to work. Depending on your company's structure and size, you can take the matter up with HR, the HR Head, or perhaps the reporting manager's manager. In most cases, the company will not deny leave just for the sake of it.