Time of supply of service when GST on services is payable on basis of reverse charge :
As per section 13(3) of CGST Act, in case of supplies in respect of which tax is paid or liable to be paid on reverse charge basis, the time of supply shall be the earliest of the following dates—
(a) the date of payment as entered in the books of account of the recipient or the date on which the payment is debited in his bank account, whichever is earlier; or
(b) the date immediately following sixty days from the date of issue of invoice or any other document, by whatever name called, in lieu thereof by the supplier.
Where it is not possible to determine the time of supply under clause (a) or (b), the time of supply shall be the date of entry in the books of account of the recipient of supply – first proviso to section 13(3) of CGST Act.