Caste certificate

Query : 1961 Born and brought up in Kozhikkode. Caste Hindu - Saliya mentioned in my SSLC & Fathers SSLC, which is under OBC. Mother is not Matriculate and alive. Went to Mumbai in 1983 for studies & employment, Now 38 years in Mumbai. Mumbai Address in Aadhar, Ration & Voters cards. Married to a Mumbai Hindu girl. For my Daughter's higher education, need caste certificate. We are not in possession of my father's Caste certificate, only record is his SSLC. Applied for Caste certificate in Mumbai but rejected b'se we were not migrants prior 1967 cut off. Applied in Village office but rejected due to present address not in Kerala. Applied in Taluk office, rejected, but given a letter to Mumbai Tahsildar stating of facts till 1983 and for needful action. Mumbai Tahsildar again rejected stating 1967 cut off. Again approached Tahsildar Kozhikkode, they refused stating that after I went to Mumbai, no records to show that there is no change in Caste ! Now I am back to square one. Please advise ways to get my Caste certificate issued. Baburaj