Company not relieving salary of notice period

My company is laying off few teams. In my case, Since we both have 3 month notice clause in appointment letter. Head is agree to pay 3month salary not at once but by every month, Mean next 3 consecutive month, with a clause (which is not part of appointment letter). In case if i get any kind of job or commercial arrangement may be a small time. They will discontinue my pay. Also, in this notice period, he do not want me to be in office. Concern: 1. Is this legal way to consider notice period by company? Or they need to pay at one go as Full and final settlement. So, I can peacefully look out for opportunities. 2. In case they stop paying me a month or 2 later with any damn thing, what needs to be done?