Can retroactive legislation defeat financial expectations based on the law in place before the retroactive amendment?

I reject the appellants’ argument that juristic reason cannot be provided by retroactive legislation. This deeming provision supplies the juristic reason for the enrichment and puts an end to the appellants’ action for damages for unjust enrichment: Garland v. Consumers’ Gas Co., at para. 49. There is no doubt that retroactive legislation can defeat financial expectations based on the law in place before the retroactive amendment.