Vat on completed apartment

Hi All,

I am buying an apartment from the builder. It's ready to move (completion certificate is already obtained). He is not charging me any service tax. But he is saying that i need to pay VAT to the government as registration will not happen without that.

I've explored this on websites and found everywhere that VAT is only applicable on under construction apartment. I've sent the website links to my builder but he keeps saying that registration office is not registering without paying the VAT.

Can anyone throw more light on this?