I made the exact same comment to the Customer Services guy from a Honda dealership. Had numerous bad experiences. The dealership fails to realise that it's very easy to absolve responsibility, but a customer's negative experience can affect their sales. I sit in an open plan office and my conversation with Honda over one of the issues they disputed, was overheard by a colleague. Her husband was planning on purchasing a Honda Jazz. After hearing about my experiences with Honda, they ended up purchasing a Hyundai. Last month met someone who was planning on purchasing a Ballade. Again, after hearing about my recent experience with a Honda approved panelbeater and Hondas non-interested response, they now looking at a VW product.
I would assume that one of their mechanics, who does private jobs at home, swopped the OEM part from your car. Or, a trade-in was being prepped for the showroom floor had an issue. They replaced the faulty part with your OEM. What goes on at dealerships is shocking. Just glad that from 01 July we not compelled to service at stealerships.
Always inspect your car inside and out after a service. Your would be surprised what could have been swopped. Unfortunately, for components not visible - you would not know until it breaks.