Sebi - SEBI Not taking proper action against the stock broker company

Geojit company has created a demat account as a joint account holder format. The account is in the name of my father and grandfather. This account was opened in **** by my uncle (father's brother), without even the knowledge of my father, and also few transactions were done. After my grandfather expired, we found few reliance share certificates (in joint names of my father and grandfather), and after probing into it, we came to know about this demat account existence. To ensure if this account was properly opened using valid documentation and signature, we asked the stock broker to provide relevant data, but the company refused saying that the primary holder has expired. Complaints have been made to SEBI, but SEBI was biased and didn't even reviewed the complaint properly. The stock broker (Geojit) clearly mentioned that if SEBI provides approval, the data can be shown to us. In this regard, SEBI neither helped in providing the data nor telling any procedure for this situation.
The surviving holder, who is my father, wants to validate this account. Please help to get the required details from the company.