Overselling service requirements.

Asked service to please change a light bulb (the right turning light, to be specific) which the car’s computer picked up as defective. Mercedes menlyn quoted me R21000 for the fix. After phone call from the service agent about the quote it became clear to me that they were trying to get me to believe that the entire front Headlight needs to be replaced. I then asked the service agent if the whole engine needs to be replaced if I want to change the oil? Just to make my point. In the end, they realised they weren’t dealing with a fool and continued to replace the bulb only Which turned out to only cost R238. I still wonder, how many other customers have they not ******* in this wat? Replacing both brake pads and discs, when only the pad are worn? Just to make a sale on discs which are way more expensive, without the client realising they have been *******? So many ways to fool a client, and its clear to me they try...