as it is a garage, you have to use the same for parking a car. it may be commercial or otherwise.
if you purchase the garage for commercial purposes stating the same in your deed of conveyance, then there is no authority to stop the same.
admittedly the garage is legal and the co-operative society is permitting you to carry on commercial activity and you have complied with other required formalities for commercial use but it is also correct that it is a garage. so you have to use the same for parking a car which may be commercial or otherwise.
in that event you may apply for a tricks towards co-operative society.
as you told that there is no provision where a car can get in to that garage, you asked to the society for the ingress and egress arrangement so that you can you the space for car parking as one of the member of the society complained of against your commercial use.
you have provision to change the usage of the same to the municipal authority.