Mutation of resale flat under Bidhannagar Municipal Corporation,Kolkata

We applied in prescribed form for mutation of our flat purchased under resale & submitted the following documents: 1) Self attested copy of registered sale deed(both side) of previous owner, 2) Self attested copy of registered sale deed(both side) of present owner ie we 3) Self attested copy of possesion letter issued by previous owner in our favour. 4) Original mutation certificate in favour of previous owner issued by Rajarhat-Gopalpur Municipality. 5) Original property tax receipt for the taxes paid by previous owner upto March'2017 issued by Bidhannagar Municipal Corporation. 6) Occupancy Certificate issued by Rajarhat-Gopalpur Municipality for the housing complex.& 7) Provisional sanctioned plan for our block having our flat. But Bidhannagar Municipal Corporation issued a letter asking us to submit the following documents: i) Porcha of the land, ii) Approved completion drawing as mentioned in occupancy certificate issued by competent authority, iii) Approved building plan from competent authority,& iv) Khajna receipt Inspite of our best effort for the last 2 months we could not arrange the above documents neither from our Flat Owner's Association nor from the Builder/Promoter. We are in a fix and don't know what to do. Waiting for kind advice.-Tapas -