Regarding the FNF and service letter - resign on spot due to family emergencies by informing my TL

I requested HR to expedite the FNF process and provide a service letter after I pay the overdue payment. Also, they mentioned that they will see if they can provide a service letter, not a guarantee. Also, for the expedited process, they said that they will process only after 45 working days. I have resigned on the spot due to family emergencies I informed my TL then, and they are calculating my notice period. What should I do?

Notice period mentioned in the appointment order and agreed by employee shall be complied.waiving it is the discretion of the employer.. If by back of notice period is there in the appointment order, that can be adhered to.
Unfortunately in india there is no legislation on final settlement.