Company Asking For Recovery In Lieu Of Notice Period

I resigned from my job on February and gave a notice email. I did not mention last working day. The company policy is 3 months notice. I requested the company to let me know of my last working day as per their discretion. I never demanded a short notice period and insisted that I would serve as much notice as required. The company asked me to work till March end (their decision solely). I submitted all the papers by March end and finished exit process. However final month salary was not paid. When I asked for F&F settlement they are asking me to pay them for not working full notice period. I have only the resignation mail that I sent. They did not sent an acknowledgement and communicated only verbally. What can I do?

There is nothing much which can be done,if you let such important instructions remain verbal.
How much are you due as Fn F and how much is one month notice which is to be paid?
You may have to strike a compromise with the company.
It is not clear you say you resigned-what is the date of resignation you specified?

The object of the obligatory clause of notice in the matter of exit is to enable the other to find out an alternative option. When you know well that the notice period to be served by you is 3 months, without mentioning the proposed date of your relief as per the contract you have asked the management to exercise their discretion in the matter can also be understood as you are prepared to pay for the unexpired period of notice if any in the event of your earlier relief. The management would have thought it possible to search for a substitute within a month or so while verbally asking you to be with them till the end of March and would have actually found out a better substitute for you and therefore relieved you and with held the last month's salary in lieu of the unexpired notice period. The management just played smart. Better try for a compromise as suggested by Mr.Rao.