> You must offer a refund to customers if they’ve told you within 14 days of receiving their goods that they want to cancel. They have another 14 days to return the goods once they’ve told you.
> You can ask the customer for proof that they bought an item from you. This could be a sales receipt or other evidence such as a bank statement or packaging.
> It’s illegal to display any notice that deliberately misleads consumers or deceives them about their rights, eg a sign that says you don’t accept returns or offer refunds.
USA is state dependent but the EU provides similarly strict laws to the UK.