It would depend on Singaporean law, which, in this case, would be the Sales of Goods Act :
https://sso.agc.gov.sg/Act/SGA1979#pr24-
I've only had a quick scan, but it seems that once payment has been made, unless otherwise agreed, the seller must deliver the goods to the buyer (Part IV, Article 29) and the buyer can claim that goods have not been delivered to them if the goods are lost or damaged in transit (see Part IV, Article 32, Paragraph 2)
To me, this reads that the seller is responsible for the goods reaching the buyer