Dont worry about it.
It is clear that the builder is taking everyone for a good ride.
T he builders should not recover any GST from home buyers since the effective GST rate on “almost all” affordable housing projects is eight per cent which could be adjusted against the input credit.
So far, the option of getting full input set-off credit that developers enjoy on under-construction projects is not be applicable on ready-to-move-in flats. This could effectively mean higher costs for homebuyers of ready-to-move-in flats, say developers.
"In the current arrangement, while developers might still get some benefits for projects that are in nascent stages, they will have to bear the tax burden for the ready-to-move-in projects since they are kept out of the GST ambit,"
There are many taxes and duties that a developer pays on the procurement side, such as Customs duty, Central Sales Tax, excise duty, entry tax, etc. These are subsequently passed on to the final pricing of the units and, thereby, to the buyer. As GST proposes to roll multiple taxes into one, the cost of construction will come down.
You may ask the details or specific law for the demands made by the builder in this regard after which you can take him into task or refuse to pay him any money and resort to legal steps in this regard.