Hi Rory! I post on both Dealer and Manufacture's account and link with @which? @whatcar? and any car magazine organisation. That's when they take notice because now thousands of people potentially can see your tweet.
At least you get a quick response and as long as you get problem sorted out, it doesn't matter if it goes into private message. At the end of the day, we are not here to make the dealer bankrupt-we just want to get what we paid for, which is good customer service. If they fail to deliver, we should inform them get the matter sorted, and if they value us as loyal customer, give us goodwill gesture.
I always give out complimentary comments on Social Media where it is due, especially if they acknowledge my problem and give me something in addition.
Ultimately, the dealers in Edam's example highlights law breaking-Consumer Rights Act 2015 states " how services should match up to what has been agreed, and what should happen when they do not, or when they are not provided with reasonable care and skill;" In all complaints, this should be quoted because if anything you can take them to Small Claims Court if matter is not solved. Or if you pay by Credit Card, 1974 Consumer Credit Act means the credit card company is also liable for the mistake the dealer has made.