• Applicability of ST and VAT today

Hi, I am a nri based in Dubai and have purchased a property in Navi Mumbai Wadhwa builders. Couple of years back they were ready to give possession at which point of time last instalment was due from my side. However since the builder has not received OC I had not taken possession . The original agreement was registered in 2010 when the property was under construction. Now I want to complete the payment though they have still not received the OC. However the builder is now charging MVAT and VAT on the final instalment due, though he has not given me a formal invoice. AM I liable to pay MVAT and Service tax now that GST is applicable. It looks to me as if the VAT and service tax will go into the builders pocket. Kindly clarify