12. Time of supply of goods.

(a) the date of issue of invoice by the supplier or the last date on which he is required, under [***] section 31, to issue the invoice with respect to the supply; or
(b) the date on which the supplier receives the payment with respect to the supply:
(a) the date of the receipt of goods; or
(b) 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
(c) the date immediately following thirty days from the date of issue of invoice or any other document, by whatever name called, in lieu there of by the supplier:
(a) the date of issue of voucher, if the supply is identifiable at that point; or
(b) the date of redemption of voucher, in all other cases.
(a) in a case where a periodical return has to be filed, be the date on which such return is to be filed; or
(b) in any other case, be the date on which the tax is paid.