Poor Customer Service

On Monday, 12 August 2024, I phoned them to arrange that they swop my husbands tracker from the BMW to the Datsun after we sold the BMW. They said that they will phone me back. They never did. The BMW went all the way from We Buy Cars Brackenfell to Durban. I can still see it on the tracking app. I phoned them on Friday, 30 August, to cancel the BMW because they NEVER phoned me back, but then they wanted me to pay the rest of the contract. Why would they want me to pay to cancel it when I wanted the tracking device transferred to another car but they never did their job? I refuse to pay the invoice they mailed and I refuse to pay anything more for that device.