Maintanence and Electricity charges without OC

I had brought a flat in April 2017, that time builder said he will be getting OC in next 6 months as he had applied for it. He also told he had applied for MSEB meter & water connection that will also be installed in the next 6 months. And builder has collected 1 lakh rupees as a maintanence fees and then only he had given the keys to us on 2017 April. And in August 2020 builder is calling us and asking the electricity charges which is provided by them in the last 3 years, and they have justifying it by installing a local sub meter before 3 months during the lockdown and saying we want to pay rupees 2.1lakh. Plz kindly suggest me. 1. Can builder can take maintenance charges form the buyers without OC of a building. 2. Is it legal for the builder to put his own unauthorised meter without informing us and asking electricity payment for the last 3 years. 3. By building does not have any fire resistance doors at the electrical and fire shafts. And even the floors are not closed inside the electrical and fire shafts. Without this can a builder can get Fire NOC or OC?