1.If you can not serve the notice period then you will have to pay the salary for those months.

2. SO THEY CAN FORCE YOU PAY THAT AMOUNT BUT NO FORCEFUL WORK IS POSSIBLE AGAINST YOUR WISH.

3.In that context send them an e-mail stating your willingness to pay the money in exchange of work in notice period.

4.If they still harass you, complaint to police can be lodged.

if appointment letter mentions that you have option to serve the notice period or make payment in lieu thereof then employer cannot force you to serve the notice period

Even if it is discretion they cannot force you to work without your free will.So do not count on their right of exercise of discretion.

It is bey0nd the purview of law to force someone to work like a bonded labour.

if the wordings used are it is at the discretion of company to accept salary in lieu of notice period then only company can force you to serve the notice period

other wsie company cannot force you to serve the notice period

You can tender the resignation and can communicate the same by a registered post with your decision to pay compensation in lieu of notice period by mentioning the clause in the employment offer letter in this regard.

Dont worry about the employer's resent about this or even if he refuses the same, you can issue a lawyer's notice quoting the conditions of the employment and demand justice as well as relieving letter and F&F settlement.

If it is not mentioned on the appointment letter that this is at the discretion of the company whether you can buy back or not then can they force me to continue and serve the notice period?

You verify this clause in the employment offer letter and revert with confirmation for more suggestion on it.