If they say that the panels weren't from a crashed bike and they are then they have to take them back - if that's what you want.
You are covered under the distance selling legislation/act/thingymajig/ask NBs996.
They sound like they've joined the queue of ever dodgy people trying blame 'mismatched expectations' and trying to make you feel guilty or precious about your fairings so they don't have to do anything about their dodgy selling practices.
Nail them to the wall!