Maintainence/Handover Related

Hi, I am a member of society in Bangalore where Builder has recently handed over the maintainence to the association and have some queries regarding the same as below. a) Builder has provided us with the letter filed for issue of OC to KIADB dated 22nd July,2019 and final OC was recieved as on 9th December,2019. He claims that post one month of filing of the letter (22nd Aug,2019) OC is deemed to be recieved and he initiated maintainence charges effective October,2019. Can he charge maintainence for period of Oct-Dec,2019 as OC was not actually recieved till than? b) Is the builder on handover to association legally liable to provide audited statement of expenses for the period of maintainence done by him? c) In handover Builder has mentioned that audited books can be prepared and shared but as under contract he has charged advance maintainence and even Oct-Dec,2020 billing at Rs. 3 PSF however, he claims that actual charges are more (Rs. 4PSF) and in case he provides audited books of previous year maintainence than he will charge for any additional amount (e.g.- Rs. 1 PSF willl be charged extra if maintainence for previous year averages to Rs. 4 PSF/month) to all residents and in case of lesser maintainence he will pay a refund. Can he force residents to pay extra maintainence charges for previous year? d) He has paid Property tax for 2019-2020 and Bescom electricity charges (No separate meter was installed) and earlier verbally had mentioned these will be waived off but now wants to charge the same to residents/ Can he do that?