worst service

I purchased a new vehicle, the insurance required a tracking device to be installed, so obviously because I have been an existing cartrack client, i contacted them to assist. I decided to sell one of my old vehicles, so after my telecom with a cartrack agent, they advised that they can either remove the old device from my old vehicle and install it into my new vehicle, at no charge or they can do a new fitment which will be charged at R600.00. I chose the first option. After everything is done, i received my installation certificate, i see an amount of R600 was debited from my bank account. I followed up with them and eventually got in contact with a lady Bianca Julius. After sending her all the whatsapp conversations, voice recordings and the installation certificate where it clearly states "reinstallation" Cartrack still wants to tell me a new device was installed? My question is, why did they install a new device if my agreement with them was to remove the old device and reinstall it into my new vehicle?? Why should I pay for something if that was not what was agreed on between myself and them? I have been a loyal client and referred so many people to this company!