Builder payment for society NOC

This question pertains to Maharashtra state. I am looking to sell my flat in Dombivli and am in advanced stages of negotiation. I am first owner and hence understand I need to clear maintenance dues and transfer charges (50%) but to my surprise found another 1.13 lacs under the head "builder charges" and remark "common areas". On enquiring, found out builder is charging society for some of the expenditure it incurred between Nay 2019 and May 2021 such as providing water tankers, etc, as there were water issues. I am told the charges also include the amount builder paid to lay new water supply pipes to the cluster. My flat has been always vacant and I have not used any of these "services". Besides it's a given that these are bare minimum that an owner expects to have in society. The fact there was a water shortage should not be a home owner concern as one normally expects these things to come with the flat.. I think this is plain robbery and the builder, being a very large name, is confident people would not fight it out legally for 1 lac.. Are they justified to ask this? I paid 2 years maintenance at the time of possession in May 2019 and I don't think I am liable to pay anything above that general maintenance of property.