False advertising

Went in store to look for a demo. I was shown this amazing polo which was affordable and all. I took the vehicle. A few months later it’s time for me to take the car for service, I’m told the car wasn’t serviced by VW. I later get a piece of paper saying it was serviced by AVIS and that the car isn’t a demo. It’s second hand. So I was basically given a second hand when I asked for demo. Now I have a problem of having a car that wasn’t serviced and it’s not even to my specification. VW lies to get cars off their floor and when you contact them to fix their mistakes they change their stories