Vat on property in maharashtra

I have query regarding applicable VAT on property in Maharashtra.

I have purchased flat in Mumbai, Maharashtra. Agreement was executed in Jan 2019 and I got the possession in Jun 2010. Also have a possession letter with no due mentioned in it.

Agreement value was 30 lakhs.

Builder is chasing me now a days and also posted legal notice to pay 96k toward VAT. If I don't pay in 10 days he will charge penalty.

As far as I know he never discussed anytime about VAT when we were purchasing flat and I paid all and cleared all dues. Infact, there are many in our society who are confused as VAT is builder's liability and it is builders responsibility to pay to govt from profits he makes. No ways he can pass on this to consumers who are totally unaware and never heard of VAT when we bought flats in 2009. Govt might have made amendments but it is for builder to pay and not buyers. We have already paid what he asked for and got our keys and letter saying no dues pending. 

Infact, builder never mentioned about this when he did society handover in 2012.

There was supreme court judgement in Sept'2013 saying builder's can't pass VAT on flat buyers. Though I am not lawyer, I know that nothing is above supreme court ruling.

It looks builder is attempting to get money from buyer, hoping one will pay hearing of legal notice.

Please guide and let me know if you want any information from my side.

Thank you.