Not paying gratuity, half-month salary and Remuneration

An Educational institute denied to pay gratuity, last half month salary and my exam remuneration? i started my job on 20th july 2011 in an educational institute(in saurashtra region) and worked for 6 years with same institute as Asst Prof. as per there rules i gave notice period for 1 month on 15th June 2017 and after notice period as per terms and condition i was relieve on 15th July 2017 and after they gave me my experience and relieving certificate/letter and my previous month's salary in cash (not credited in bank) till that every thing was fine but after that i went to director for my gratuity he told me to give me application and he will revert me with same after week so he haven't sign the application so i have mailed him the application and our discussion on it. so now i joined an IT company on 20th July 2017 and after a day or two i got a call from principal and management person (who is relative of trustee, and trustee is MLA) that why you applied for it, i replied its legal and you never told me that we wont give or i never signed such thing on paper. he told me "we will not give & if you want to go ahead in legal than go and keep in mind that supreme and high court is in our pocket. i told no problem and he hang up the call. i called to my director but he haven't picked my call, so i informed my department's principal that i try to connect to our director but he haven't pick my call neither he reply to it so please informed him that you told that's the reason i apply and now why he is not answering me, i even told to my department's principal that we can even sort out by discussion on it, but my department's principal told me that our director told me that if he want to sort out than we will give him his salary (last 16 days salary) and his remuneration that's it.. and till date haven't got any update for what i applied.. well i want to specify my salary details to and what an educational institute pay to their employees. my salary was rs.29000 and my account got credited to 6th pay (that is 55300 prox) and rest we have to give back in cash. cant do any thing coz they prior take our signature for same. so i want the way how i would go through and get solution