Secratary is not allowing to transfer flat in my widowed mother's name.

My father passed away last year ([deleted]) leaving behind a flat wherein nomination form was not submitted by him when building went under redevelopment. After he passed away, we went to secratary asking for the formalities to fulfil to transfer the flat in the name of my widowed mother. He asked us to make: -Release Deed 1.) Flat Details as per Share Certificate & As per PAAA 2.) Indemnity by all Releasor 3.) Family Tree -Application Letter to Society & to Developer -Transfer of Flat Form -Affidavit cum undertaking We made all the necessary documents for the proceedings but my lawyer needed the NOC from the the society which states that society acknowledges the death of owner and have no objection if legal heir submits release deed of the flat. Now when I submitted all the documents (rough) I requested secratary to provide NOC to proceed further wherein he said that he was out of town and we will have to wait until he comes back. After 2 weeks he informed us that he is back in town so we talked about NOC where he kept saying that only Release Deed is not enough to transfer the name. He even talked with my lawyer regarding this matter where in secratary told my lawyers once Affidavit cum Undertaking is submitted, society will provide NOC. But he kept denying it that he didn't say any such thing. So we were ready to do formalities without getting NOC from the society (Assistant of builder told me that it is not really necessary to get NOC of the society for this matter). Later when I sent him rough documents to read and correct if anything is wrong, he told me he won't transfer the name because my father was previously married to another woman so they need divorce certificate too now. (My father and his ex wife were divorced in the year 2004 & my uncle transferred this flat in the name of my father in year 2010) Now problem here was that divorce papers were not notarized by my father, so secratary kept saying that we have to go for probate making process. Even when we said that my mother have legal marriage certificate and flat was transferred in the name of my father years later the divorce the secratary was not ready to negotiate. A few days later he called us again & said that if we take sign of the ex wife on release deed we might not have to go through lengthy process of Probate. Now here the obstacle was that we didn't knew any whereabouts of the ex wife. We tried searching for the contact and residence but we failed. Now in between my conversation with secratary he kept mentioning that my father was annoying and kept ignoring him for nomination form. And in one call I, secratary and the lawyer had heated conversation where he said “ab toh me hone nai dunga probate k bina dekh lena". And by mistake I sent one audio clip to him instead of my brother (which i instantly deleted) maybe he didn't play hence he kept asking me to send again. So now i feel he is just being child and taking revenge. Any advice?