gst applicable on partial payment made before 1/7/2017

gst applicable on partial payment made before 1/7/2017

I booked a flat in december 2015 at a cost of 40 lac
i took a sbi homeloan
Before 1/7/2017 i paid 36 lac (inclusive of bank part)to the builder in different installment(,all payment done by cheque.)
after 1/7/2017 i have paid a sum of rs.1 lac.almost 80 % of the flat is complete.
The builder is demanding gst@12% on whole 40 lac
Iwant to know my gst liability before 1/7/2017.further what will be my gst liability after 1/7/2017.
kindly respond with relevent regulation and circulars

Asked 6 years ago in GST

Have you been issued invoices in relation to the payments which have been made before July? If the payments were according to the installment structure, Service Tax shall apply for payments before July.