Two months ago my wife and I bought a second hand Skoda Citigo from a main dealership. They talked us into buying a coating for the car (inside and out) called GardX. We went for it at the quoted price of £400. I recently found the original owner's paperwork in the glove compartment and, lo and behold, it had already been done when the car was bought new using a different company but the same coating. It still had two years to run on its guarantee which was never mentioned.

I wrote to their head office demanding my £400 back. They have offered £200 claiming that I actually got it for £200. I did not. They just adjusted the invoice to make the profit on the car greater. My point is that it's not about the money, it's about sharp practice with an unsuspecting consumer. I have the original schedule and all relevant emails and paperwork since highlighting my case. Can you advise and help?