The time of supply being issuance of invoice under the CGST Act, 2017, the supplier of services must charge GST in this case. However, where the payment for such supplies has been made (prior to issuance of invoice) as advance before the 1 July 2017, the tax would be payable under the law prevalent prior to 1 July 2017, as the point of taxation had arisen before this date to the extent of the advance.
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