Company full and final

Sir i had worked with one company in gurgaon. At the time of appointment they had company ctc include ex gratia / bonus and gratuity part as per company policy in on blank paper without name and designation and on the appointnent letter they have mentioned on the gross salary and other benefits as applicable by the company .they have mentioned three month notice as per company policy and also mentioned three month salary as a lieu of salary but what is the company policy it is not mentioned in any writing policy on the paper. I had given the 16 days notice to the company and they have deducted two and the half month notice pay include gross pay as they have release only 10 % as exgratia to the diwali but not release the balance 10 % ex gratia and also the current year ex gratia anx the gratuity part of two year and nine months as they are not giving any benefits to me as they are showing in the yearly components but whenever i was asked the company policy they are not provifing in written and they hsve threatened to a legal suit against me right now very depressed i dont know what i will fo they are deducting the notice pay but not giving the ex gratia part pls advise me mercy request what i will do my family andmy self are in very stress