I would be pissed off and let them know that. The spoiler is $90.00. If the negative social media press value is less than $90.00 to them then you are going to be out of luck. I would make it very clear to them that you intend to be very vocal on social media about your experience and if you cost them one sale of a new or used car that would more than cover this spoiler issue. Sounds like they have no integrity so they probably won't budge. Glad I don't have a dealer like that!