Maintenance charged by managing committee even though no OC and no possession letter by builder

Dear Sir, This society is Marvel Arco , built by Marvel builders , Pune. I have paid all the payments due towards the flat as per the agreement , but the builder has still not given the possession letter for the flat. Also the B wing , the one in which i have my flat doesnot have any OC. It’s just recently that they received the CC. But long before this almost 70% owner’s occupied the flats because of personal reasons. Since the flats were occupied they decided to take maintenance from all flat owners at 5000 pm. And continuously they are charging the dues with interest of 21% for non payment. I have told them that i still donot have the possession letter from the builder and neither am i occupying the flat & besides all this the society still doesnot have An OC, so under these circumstances you cannot charge any maintenance from me. Also i have paid the society a big amount towards society maintenance as per the agreement. But the MC is not giving any reply. And even the people who are already residing in the flats without any OC have also not taken up the Matter. The amount is slowly creeping and then it will become a big burden for me and then this matter will become a legal matter. Kindly advise.