Sanklecha Constructions Private Limited - Builder is not paying Pending Property tax

I have purchased flat from reputed builders in Pune. Flat is legally registered on my and my dad's name and I got the possession in December ****. We received the pending Property tax notice from Property Tax office, Pune Municipal Corporation in January **** via post. When we reached out PMC office and find out more details around the notice they confirmed Builder never paid the property tax for this property which pending since **/**/**** to **/**/**** = Rs *****/- + *% fees applicable per month. This property Tax notice is on his name.

I tried to reach out to builder via phone call, messages but did not get a response from him. I have sent him an email and requested him to pay the pending amount in ** days which he did not paid. I again sent him reminder. Now I am lodging a complaint.

I have bought this property for my eadrly parents and they are living there. Because this whole thing they are very tense and frustrated as builder is not responding to our request.
Could you please advise what will be the next steps since builder is not responsive, not willing to pay the dues and also not transferring the property tax liability?