It’s not really impossible to do refunds to consumers. Businesses wouldn’t have to be compelled to cooperate either. If they are suitably enticed, they will go through their own records, find rationale for higher prices because of tarries and submit individual records to the government.

Businesses are already basically forced to do KYC on direct to consumer imports so they have the information on file.

It’s only for the wider market, where items aren’t imported to be sold direct, that it’s harder to tell because as you said there is a chain of actors.