The post has enough identifying information for the shop to figure out they're about to get drug through the mud on social media while potentially having their certification suspended or revoked. That's a huge financial impact for an independent shop. Retaliation should be considered a possibility especially because they're morals are already in question.

For real though, you've already made them hate you. Do not let the car out of your sight while there. Some people can be really spiteful assholes.