Incorrect tracker installation

I've had to have my battery replaced due to a incorrectly installed tracker.<br> <br> It was claimed by my car dealership that the tracker was incorrectly installed. Subsequently, a technician was sent out twice to check up on the tracker. He resolved the issue but I still had to pay for my battery to be replaced. Netstar are refusing to claim liability as they say the car is second hand and therefore they have no proof that it's the tracker, even though a technician went out TWICE to look at it.<br> <br> They refuse to reimburse e the cost of the new battery as they say there is no proof it was the tracker, even though the fitment centre confirmed this was the case