Resignation Declined Last Minute: What Should You Do When HR Changes the Plan?

If an employee resigns on day one and waits for his relief on the 25th day as per mutual discussion, and suddenly the HR of the company declines his resignation on the 25th day and verbally informs him to wait for the next 15 days, what should be done? My query is that since no written explanation is given by HR, does the candidate have to resign again as the resignation was declined without any written grounds?

Please do not use organization-specific abbreviations in this forum. What is meant by RHR remains an enigma for the rest of us. It appears the resignation has not been declined; it is only told to wait for the next 15 days. Is it for relieving or deciding on the resignation itself? Since there is no formal communication rejecting the resignation, there is no need for a second resignation. Probably, you could discuss with the authorities and sort it out.