If your visa application has been refused, you will receive a letter from this office clearly stating the reasons for refusals. It is up to you to provide the required documents to support your application as the Visa Officers can only base their decision on the information provided.
The checklists provided in links under the Types of Visa & Supporting page of the website are there to assist you with your application so that you can provide the correct documents.
Please remember that all aspects of your application, including the supporting documents and your previous visa history, are checked by the Visa Officer before a decision is made. It is in your best interests to ensure that you have provided all of the required information at the application stage and that all of the information provided is correct.