In Feb 2011 I bought what I thought was a pre-owned Mercedes C350 Estate CDI BlueEfficiency model. I emphasise BlueEfficiency because after owning the car for a year I renewed the tax and thought that it seemed higher than I expected.

After double checking my V5 I contacted Mercedes Benz Customer Services and provided my VIN number so I could confirm the exact model of my vehicle. They wrote back to me confirming that the vehicle I owned was not a BlueEfficiency and was in fact a C350 CDI Sport.

Both my finance agreement and the original offer I received from the dealer state that the car is a BlueEfficiency model. After I received the written confirmation from MB I phoned MB Finance who my agreement is with.

I explained the issue and they stated it wasn't their problem because they only process the paperwork the dealer has sent them. They told me to go back to the dealer where I bought the car and ask to speak with the dealer principal.

I've now done this and exchanged a couple of emails. The dealer has confirmed the car is not a BlueEfficiency but has stated there is no difference in value between the two models and very little difference in overall specification.

Although initially the dealer appeared to be eager to help resolve my concerns they now seem to be very dismissive. I believe that the car I have bought is not the car I was told it was at point of sale and clearly I am paying more for road tax and overall the fuel economy is not as good as the BlueEfficiency model. How can I progress this issue and what do you suggest I do next?