Courtesy call

Was contacted by a call center as a courtesy call fro a vehicle that was brought in for a service reg DH05YZGP. This vehicle does not belong to me or my wife and after explaining this to the agent, I was told that the system will be rectified. I have since received five other call where I had to explain that we are not the owners of the specific vehicle. I then spoke to the Service manager at GM Barloworld GM, who advise he would phone Barloworld top sort out the issue. I assumed everything is sorted until I received another courtesy call for vehicle reg number CV63XXGP. Once again we are not the owners of this vehicle. This vehicle was taken in for service at Ferndale. How many courtesy call will I now receive fro a vehicle that does not belong to me. How is there such a big system error in such a big company? Who can sort this out?