Delay in providing relieving letter

Hello Sir, I am employed in a firm for last 18 months. Its a US based startup and registered in India too. I have a contract which states as below. Now i have notified the employer about my resignation formally through mail communication but I have not updated about any release date also my salary is also put on hold. I am afraid if i would be denied reliving letter to stating the unfulfillment of the deliverables. Please advice what steps I should take in order to obtain my reliving letter and due salary. 8) Notice period: a) This agreement shall be terminated by providing a notice in writing on either side. The period of notice will be 30 days for employees on probation and 60 days for employees who have been confirmed. Failing to serve the full notice by either party will be settled by paying the other party a one month gross salary of the prevailing salary for the applicable days. b) Your relieving from the services however, depends on the satisfactory completion of any assignment(s) you are working on, during the said notice period. The written notice shall be served on an official working day and the period of notice shall not include any period of absence of leave.