No. Normally, no employer will send an email asking the employee to resign because if he does so, that will become an evidence that the employee has been asked to go. Instead, the employer will only tell the employee verbally that he should go. Once he puts his papers, it will be the employee regarded as an initiate from the employee to leave. Then there is no legal issues involved, and the employer can settle the accounts which shall include salary and the leave balance, whatever is available. But your employer or the HR is saying stupidity. They are asking you to resign and at the same time saying that in records it would be construed as termination and on termination the employee is not paid any leave balance. The latter part is against the law, any way, and it will not work as per his decisions, but the former part, that resignation will be treated as termination is stupidity. When an employer is not happy with an employee, he can ask him to go. He should have the courage to terminate the employee after following the protocols involved. No law will say that an employer should keep a non performing employee in service. he can terminate him. But it should not be done in a fine morning. he should have given the employee at least reasonable opportunity to improve his performance. For that the employee will be put under PIP. After a few months, say six months, again his performance should be evaluated, and still if he is not performing he can terminate him by paying as per the provisions in the contract of employment or the certified standing orders. Normally, when the employee is ready to go, whatever benefits is payable will be paid in full. There will not be any bargaining. Simply, if the employee who is to be eliminated himself is ready to go they will not look into other issues, but they will just allow him to go. They cannot eat the cake and keep cake. Your employer wants to eliminate you, but at the same time, will not tolerate on compensation or other payments. That is what I have said that your HR is stupid one.
You need not expect the Hr to send a email saying that you should resign. But if you do not resign, they can send a termination letter. Again, you can defend that termination by moving against the company saying that there is no reason for termination. As far as possible, avoid termination. It will lead to unpleasant situations both for you and the company. The company will, in turn, take it against you and spoil your career. therefore, it is upto you to decide, whether you should fight for the leave surrender salary and subsequently spoil your career or just leave it and find some other job.