GST credit Reversal

Meet Shah (ACA) (178 Points)

01 December 2017  
one of my client deals in real estate sector He received B U on 18/09/2017 During months of Oct 2017 he received Rs.50k as flat booking no GST will be levied on the same
but now what will be the impact on GST / Service Tax Credit Taken on the same while constructing entire Build
should i have to reverse the credit ?