First of all we are not able to see your amount that you paid and it's relevant dates they have been deleted so kindly post it again.
Secondly since you had paid builder before completion of property he will charge service tax and gst if payment even made after July 2017.
Now if your area of house is below 2000 sq feet the service tax would be 3.75% on the amount paid if the area is above 2000 sq feet the rate would be 4.5% and in budget 2016 I guess there was an amendment in service tax and rate was changed to 4.5% for all construction and in gst the rate is 12%.
Hope you find the information helpful if you do please rate it 5 and provide your valuable feedback for my improvement.
Thank you