1. Treat the matter in this way. You have formed a society which has not yet been registered and the society has opened a bank account in its name mentioning the name of the secretary and treasurer who will operate the account. For that you need to elect secretary, and also board of directors. Without specifying the names of the persons and their designations who will operate the account of a society, bank is not supposed to open in the name of the society,
2. For forming your Housing Society, you need not depend on the Builder. You the bonafied flat owners can yourself form a society and elect your secretary, president and board of directors.