ex-gratia issue

dear all,
hello.
this is ayananshu form ahmedabad, gujarat.
i join this group as it is very much knowledgable.
i just want to get information regarding ex-gratia issue with my earlier employeer.
the brief history is;i was working as sr. engg. design with a mnc at baroda from 11.02.2008 and after resigning i was releaved on 06.09.2008 without any dispute. the organization provided me the offer letter and salary break-up mentioning ex-gratia as a part of ctc which is to be paid annually. also there is not a single clerification regarding ex-gratia in the appointment letter. now when i am asking for the payment, the organization is denying to pay it.
is there anybody who can guide me to come out from this issue.
thanks
regards,
ayananshu parmar.