Society Maintenance Charges

Hello Team, I had taken Flat Possession on 15th Feb 2015 after paying Maintenance Charges for 2 Years (Total Sq Ft Area x 2 RS / Per Month) which was valid until 14th Feb 2017 (and cleared the remaining deficit of about 45 days Now in the Current Month, Builder has come back stating that he's not able to manage Society since the Funds are too less and expenses are more, having said that he's asking to pay an extra amount based on 2.5 Rs per Sq Ft Calculation (Difference of 0.50 Rs) for the entire FY16-17 and also requesting to pay for the current Quarter of FY17-18 considering the same calculation of 2.5 Rs. Questions:- * is the Builder Entitled to ask for additional money although he charged for 2 years in advance. Assuming that there would be some logical calculation they must have done when Quoting 2 Rs per Sq Ft initially * The Society Handover is still not been done. Considering the completion letter approved by PMRDA it has a clause which states that Builder has to provide Water Supply (with his own expenses) until Corporation or Grampanchayat is able to provide the same. Someone told me that he's entitled to build Borewells and it would not matter if the Water is available in Borewells or not. Also if this statement is true then can the builder charge Society Funds for Water Supply?