Unhappy with Auto Xtrem Silverton

I bought a bakkie at Auto Xtreme Silverton in Pretoria. The car was okay until after a month I started getting a message on my dashboard saying “tyre press monitor inoperative “. I went to tyre shop thinking maybe there was something wrong with my tires but they told me everything was fine with my tires I just need to take the car back so they can fix the sensor and program it. I called the dealership and they said I should bring the car. I think I taken the car there three times and every time the car got back the message would be gone and I will appear again when I drive 100km speed. I went back to them and this time I spoke to the manager who was very rude and told me they can’t fix what they can’t see. After a long fight they took the car to their engineers who said everything was fine with the sensors. The message is still there. I took my car again to a tire shop and one one wheel/tire they found a sensor inside the tire hence the kept on giving the message. I am wondering how did the engineer miss that the one sensor was not connected. I’m sitting with a sensor that I have to pay for installation and programming. I would not recommend them because they will make you look like a mad person should you have a problem with the car. They ignored a lot of the messages I sent to them.