Charges at the time of Property Posession

Hi, I have an under-constructed flat in Greater Noida for which the possession was due in March 2016 as per agreement letter with an extended 6 months clause making the final possession in Sep 2016. Now the builder has moved the possession to Jan 2017. There is a penalty clause in agreement but have not received any payment from builder till date. During a meeting with buyers group they have mentioned a tentative statement of charges which shall be applicable at the time of possession. What is bothering me is the Maintenance charge which they are asking in advance for 36 months @ Rs. 2.25 per sqft. Q1. Is it mandatory to pay the maintenance charges in advance for the services which is not yet availed. Not mentioned in BBA to be paid in advance Q2. Even if the charges are required to be paid in order to take possession. Can this be claimed back by filing a case in consumer court. Q3. For delay in penalty payment, can i claim interest on the delayed payment, if yes, at what rate? Also the builder is asking to pay farmer compensation @ 50 per sqft. with a draft favoring GNIDA, however in the addendum agreement it is clearly mentioned that no charges will be levied on account of farmer compensation. Please advise a viable course of action which i can take to protest the above. Thanks Sanjeev