Section 22, The Goods and Services Tax Act, 2009

(1) A GST adjustment event occurs if– (a) a taxable supply is cancelled; (b) the consideration for a taxable supply is altered; (c) goods or services (or part thereof) that were supplied as taxable supplies are returned to the supplier; or (d) the nature of a supply, whether or not it was a taxable supply, is fundamentally varied or altered. 40 41 Post-supply adjustments for GST adjusment events. (2) If a GST adjustment event occurs and the GST properly chargeable in respect of the supply exceeds the GST actually accounted for by the supplier, the amount of the excess is treated as output tax payable by the supplier in the tax period in which the GST adjustment event occurred. (3) If subsection (2) applies and the supplier has issued a GST debit note to the recipient of the supply in accordance with subsection (2) of section 32, the recipient of the supply may treat the additional GST specified in the GST debit note as input tax in the tax period in which the GST debit note is received. (4) If a GST adjustment event occurs and the GST actually accounted for by the supplier exceeds the GST properly chargeable in respect of the supply, the supplier may treat the amount of the excess as input tax in the tax period in which the GST adjustment event occurred, but only if the supplier has issued a GST credit note to the recipient of the supply in accordance with subsection (1) of section 32. (5) If subsection (4) applies and the recipient is a taxable person, the recipient shall include in its output tax for the tax period in which the credit note is received, the following amount:- (a) if the recipient was entitled to a credit for all of the input tax in relation to the acquisition, the amount of additional GST specified in the GST credit note; (b) if the recipient was entitled to a credit for only a proportion of the input tax in relation to the acquisition, the same proportion of the amount of additional GST specified in the GST credit note; or (c) if the recipient was not entitled to a credit for the input tax in relation to the acquisition, nil. (6) If the recipient of a supply to which subsection (4) applies is unregistered, no GST credit note may be issued and no input tax credit is allowed under that subsection until the supplier has repaid the excess GST to the recipient of the supply, whether in cash or as a credit against any amount owing to the supplier by the recipient.