regarding the advance society maintenance for year

I have booked a flat in June 2019 and builder has provided OC on Sep 2019.

I have started living on flat from 14 Nov 2019 and had paid society maintenance for a year in that week.

Builder is asking for maintenance from Sep 2020 however my family has shifted to Nov 2019.

Should I pay maintenance from Sept as per OC provided?
Or
Should I give him maintenance from Nov 2020?

Please help me..

Thanks,
Pankaj Kamthe