Vat incase of resale of flats

Hi,

I have purchased a flat (Agreement for Sale done with Builder on: Aug-2006) and before possession, i had to move out of pune hence had to sale it before possession (i.e. Agreement for Sale done on: Nov-2007). And i have not paid the VAT and Builder has asked me to pay the VAT.

Now my question is that Who should pay the VAT, whether it should be me or the person who has bought the flat from me and who has received the actual possession of the flat?