If the employee has been working as a manager with managerial duties and responsibilities, the act of joining another organisation without proper handing over should be treated as a serious offence. In such case, you can postpone the exit in the official records of EPF until he submits a convincing reply. You can also hold his service certificate and give him a message that he will not be getting a favourable remarks in the background verification. If he was not having any such major responsibilities to be handed over, leave it.