Sc caste certificate for ordinary resident

I belong to SC Caste(namasudra) and wish to issue a caste certificate from West Bengal. I was born in Mumbai, however my father, grandfather and their forefathers belong to West Bengal, so as per the law clearly stated on the wb sc caste certificate website which states that those residing in WB before 1950 disregard of where they stay right now are entitled to be considered as SC of Westbengal. There was a checklist mentioned on the official website of WestBengal and all the documents required were produced by me which included 1) My Fathers SC certificate (issued by wb govt) 2) His passport and School leaving Certificate (for residence proof of WB) 3) Family blood line and certificate of residence from Anchal pradhan and Gram Panchayet 4) Tax Return of our land in west bengal 5) My Birth certificate/Pan & Adhar Card (citizenship proof) These were the only documents required as per the official website of sc certificate issuing authority. However on my day of document submission in BDO office, my application was rejected stating that I do not have any proof of permanent residentship (which included my election card, ration card) According to them untill & unless I do not produce that, they wont accept my application. Even after I urged that I had all the required documents as mentioned in the official website they said that fathers or applicants voter id is necessary which completly contradicts to the info provided on the website. Kindly help, Regards Mrinal Majumdar