November 21, 2016 with the Christian Medical College, Tamil Nadu, India (CMC) for construction of 'Service and Teaching Facility' at CMC. As per the Agreement CMC was required to pay 5 percent of the contract price in two tranches of 2.5 percent each totally amounting to Rs.15,83,72,000/- as 'Mobilization Advance' to the appellant. Both tranches of 'Mobilization Advance' were paid to them by CMC during the Pre-GST regime. On receipt of 'Mobilization Advance' the appellant had paid Service tax on 40% of the amount received(after availing the abatement), as Service Tax was leviable/payable under Sec.66B read with Sec.67 of the Finance Act, 1994 on receipt of the amount. However, no Value Added Tax was paid on Mobilization Advance as VAT would be payable subsequently only at the time of charging Running Bill (RA Bill) on the gross amount including the 'portion of the As per the agreement, the Mobilization Advance' being adjusted thereon. 'Mobilization Advance' had to be adjusted in fifteen equal installments on monthly basis against the Running Bill during the month or separately if no Bill is raised in that particular month. As on 30th June 2017 they had paid five installments of first tranche and three installments of second tranche of Mobilization Advance totally amounting to Rs.4,22,32,533/-. With the implementation of GST from 01.07.2017, the payment of remaining ten installments of first tranche and the remaining twelve installments of second tranche of the 'Mobilization Advance' totally amounting to Rs. 11, 61, 39,467 /- transitioned into the GST regime. They had filed TRA N- 1 Return in terms of the Section 14 2 ( 11 )( c), under Transitional Provisions (Chapter XX ) of both CGST Act, 2017 and TNGST Act, 2017 for transferring the amount of Rs.1,44,85,057 being Service Tax paid on the 'Mobilization Advance' under Sec.66B read with Sec.67 of the Finance Act, 1994 during the Pre-GST regime. During September 2017, this amount has been transferred into GST common portal and credited into their Electronic Credit Register. It is the view of the appellant that the portion of 'Mobilisation advance' transited into GST regime would get covered under Section 142(1l)(c) of CGST Act/TNGST Act 2017. Their client Christian Medical College, Tamil Nadu, India (herein after CMC) has disputed this and they are of the opinion that the portion of the Mobility Advance transited into GST regime would get covered under Section 142(1l)(b) of the TNGST Act, 2017/CGST Act, 2017 as Service tax was leviable on 'Mobilization Advance' paid for Works Contract, under Chapter V of the Finance Act, 1994 and no VAT was paid and as such no GST shall be payable on this under