sales & service tax

Hi all

I took a flat near Tarnaka, Secunderabad. The total cost is Rs 56.5 L.

I had paid 55L (white money) till now and have to pay Rs 1.5L.

But today i received a letter from builder that, I have to pay around 2.5L as Sales & Service tax for the 55L what I had paid.

Sales tax @1.25 on 55L and Service tax 3% on 55L.

As I am hearing this for the first time, please clarify whether is it necessary to pay this. I am totally confused seeing this unexpected charges.


Please share your opinion. It will be of great help to me.


Thanks