Maintainence charges without oc and noc of project. possession taken

We booked a flat in Gurgaon in 2009. Builder (Reliable Realtek) delayed the project and its still not fully completed. Basement work is pending in half of the project and few flats are still to be completed in few towers. Our flat got ready in 2019 and due to so much delay we wanted to save rent and we took the possession without receiving an OC on this project and started living in the society from May 2019. We paid 1 year advance maintainence also at the time of possession but as OC was not available, builder informed us that the maintainence charges will be applicable only once the OC will be procured. Now suddenly the builder have started charging the maintainence charge from Jan 2020 and assigned a maintainance agency by himself without any information to us. OC is still pending and work is still pending. Builder provided the services of Guard, Electrician, Plumber etc. But those workers were the one who were completing the pending work in other flats. Can they charge maintainance without completing the project and without any information, RWA or assign a maintainance agency without getting any legal document from govt?