Audi of Melbourne / Melbourne Fl. Christian Paul / sales manager. I was sold a used Audi A4 and told it was not wrecked and had a clear carfax. WRONG!!! Internet

I had bought my 2007 Audi A4 in September of 2010 from Audi of Melbourne. A year or so later I received a letter saying" We Want Your Audi!". I took it in for an appraisal and basically was accused of wrecking my Audi in 2009 and they would only give me 8,000. for a "wrecked" car.
I Bought it from Audi of Melbourne in 2010! They had sold me a wrecked car with a false carfax , Plus it was certified through Audi of Melbourne of having no damage or defects!! When I tried to reason with them as far as splitting the difference, I was told No. They said they would give me what it would be worth if I would like to buy an other car from their dealership. Really!! ?? I spent 26,000. and you'll give me 8 to 13 grand if I buy an other one from you! All I want is half of the difference between a used wrecked A4 and a non-wrecked A4. That's all I was asking, I would split the loss with them.... I was told No.. I now have learned not to trust any CarFax coming from Audi of Melbourne nor their mechanics who certify " previously own cars" Even I, after the fact can see where the car was hit and I'm no Certified Audi of Melbourne Mechanic. In my own experience with Christian Paul, I found him to be accusatory and arrogant toward me as a customer.
I haven't seen a lawyer yet, but that will be my next step. It's only my opinion, but I feel I was deceived and nothing was done to rectify the situation to my liking as a customer.