Very bad service

This is a very bad company, when it comes to payments! I had 1 unit in my vehicle, then I sold that vehicle and got a new vehicle with a new unit. I paid R2600 cancelation fee, now they still deducting for 2 units and telling me I owe R2600 1 day and the next day, the amount is different again, pathetic company, they can't even do their admin, how can they track a vehicle.