Denial for using common amenities

Hello, I have purchased a resale flat in Apartment Society in Vadodara. The first owner has not paid one time Maintenance to builder but Sale deed was done between them before 4 years. The first owner never stayed in that flay it was kept vacant. So now as I was not aware of any association formed by initial 8 flat owners, they have asked me to pay pending monthly maintenance and I paid them. Now they are asking for transfer fee of INR 35000 if I want to be part of society and use common amenities. So I asked for society registration paper and shares, but they where not having any of it. They only have a notarized document for creation of association within apartment but that also out of total 36 flats only 8 person have signed it. So now they are forcing us to pay transfer fee and one time maintenance to use common amenities like Gym, common hall. Also, my elder brother own a flat in same apartment and they are denying him as well to use common amenities. He has purchased directly from builder and has no dues. Thanks for reading and giving your time. Would welcome any suggestion to overcome this situation and live peacefully.