You can immediately contact your DP and ask for an explanation on why the DRF got rejected. The DP can immediately check with the concerned registrar and apprise you on the same. Normally, the reasons are quite technical and you can just rectify the error and resend the application. That is why it is always advisable to double check all the paperwork before you send the DRF. That can remove 95% of the objections and rejection chances. If there is an issue of duplicate certificates or fake certificates then the process gets a little more complex as you will have to then file a police complaint and also go through legal formalities for resolving the issue.