Resignation Letter submitted but not accepted

Have patience and understand the problems of the employer.  You are aware of the time courts take for taking a decision and the machinery involved in giving such relieving certificate.  Focus on preparation for the examination and this relieving will not hamper in any way for the present.  You must be successful, then appear for an interview and then submit those documents and all this procedure take a minimum of one year.  By that time you may receive your relieving letter.  You can meet the concerned and explain your fears and can request such relieving.  The normal time in any organization takes a minimum of one month. for reliving an employee and notice period is required for all these exercises.

Wait and watch for some time.