Dishonest sales representative Dart motors

Purchased a car from the dealer just about a year ago. When purchasing the car we my wife and I was promised that we purchasing a car with a " new" engine. So we were so happy which i am sure anyone would be knowing you getting a great deal. Little did we know it was just but a sales pitch which got us sold. This was not our first purchase and hoped that we would receive the same honest, professional service as per our first purchase. Well the so called new engine has done just about 10000 km and its finished. Yes dead and parked at the mechanic who has no belief that this was a new engine. I did not expect a new car or no problems but i believe in honesty. The so called new engine had used parts included which boggles me. Which boggled me too was the sales representative asked me to get the car serviced after we purchased it. New engine serviced? After much diagnostics done i am more the wiser thanks to technology and mechanic of course. Whats saddens me is to have been exposed to absolute excellence on our first purchase to what we received on our second purchase. I am paying Dart motors every month with no default for a car that has been more parked( mechanic garage) than on the road. Sadly this was my wifes favourite car which now has become her worst. Sorry BMW but we received a dead one here. We had the car sent for roadworthy test after purchase. Then we were informed that we need to replace the rear brakes. But no error on the car reflected this. When the mechanic removed rear wheels to check they found the brake wiring have been tampered with. So no error would be sent to the computer to say brake pads need replacement. Fortunately have our mechanic all needed footage and we obviously have all the bills paid. This sadly will be our last ever dealing with Dart motors as honesty is very important to us.