The company can do whatever, the consumer or a consumer protection agency would then have to sue, so this is highly asymmetrical (against the consumer/fraudster

The company can do whatever, the consumer or a consumer protection agency would then have to sue, so this is highly asymmetrical (against the consumer/fraudster) in the individual case. A company trying to scam people like this by claiming return fraud would likely find itself in expensive hot water once the pattern became obvious though. Avoiding the risk of having to deal with this is one of the reasons why people buy via Amazon (aside from convenience and fast+cheap shipping).