Great until you take the car

We purchased a car from Pinnacle Cars in Randburg 3 weeks ago. Initially they were very good, quick service, helpful etc. But, the car we bought has a consumption rate of 10 litres per 100km, when it should have had a rate closer to 6.5 litres. There were other issues, like water leakage, terrible keys and so on. We sent the car back to be fixed, and while the consumption rate improved to 8.3 litres/100km it is still not what it should be (we have owned the same model previously and know what it should be). The key that they fixed does not unlock the door, only the central locking works, and you have to put it into the ignition a certain way in order to get the car to turn on. But, Pinnacle cars will do nothing about it, and say that it is within acceptable levels - this is such a half-hearted lets-save-money-where-we-can job. I have emailed, sent messages, requested that they switch the car all still within the 1000km warranty period. But zero feedback unless I contact them. Beware the purchase of a dud car - you will get no help from Pinnacle Cars.