How to prove i am unmarried to govt as they had decided

From your quarry it is not clear that the objection has been received by you in writing or not. If received in writing you may ask the sources of information. In your reply you may confirm catagorically that you are unmarried. You can also attach an affidevit with your letter in this regard.

However,  while paying compensation it does not make any differrence that the daughter of the deceased is married or not. It is to  be paid on being the daughter of the deceased. It is to be disbursed as heir of the deceased as per the sucession act. Before taking the legal steps you may refer your full case to the Head of the Trust. You should mention in your letter the hardships faced due to undue delay being caused in payment of the compensation, Once the award of compensation is rejected in writing by the trust you may approach the court according to the grounds of rejection of the claim. You may also take the assistance of the Port Trust Employees Union for early settlement of the claim.

You should submit an affidevit regarding your being unmarried. If the Trust does not accept the affidevit legal way has to be taken.

Mr.Rajender Kumar suggession is right.

1) You being a legal heir being married or not doesn't matter.

2) Even if they insist provide an affidavit to them.

3) Approach or write to higher authorities and keep all copies and acknowledgements with you if you need to drag them to court.

If company is not providing the details with document who said to them during varification that you are married. Ask them information under Right for Information Act 2005. The clear cut order of the labour act is that gratuity amount to the legal nominee be disbursed withinin 30 days from the submission of death certificate to the employer.

I partially disagree with Mr Clone_Pavel.  You are not claiming this job as a legal heir. You are claiming this job as child of a deceased employee just because the family is in indignant situation due to death of sole bread winner.  Further sinc ethe assertion has come from Secretary there may be hadly any aujthority higher than him who you can meet.  You can try meeting the charman.

they have no right to assume that you are married. 

You can quote such conversation and send Rs 10/- IPO to the same authroity and seek source of information as to on what basis they beloeive you to be married.

Although compassionate job is not a inherent right but state funtionaries are bound not to act arbitrarily and you canmove to court if there is no other reason to deny you appointment.