no charge while under motor plan is a myth

I recently purchased a used BMW still under motor plan. Before I purchased this vehicle it was sent to Bruma Auto who went through the vehicle and the history for me. I recently booked the vehicle in for a service at Autobahn which I must say went very smoothly. My complaint is as follows. The service advisor informed me that I needed to change the vehicles ownership on their system at a cost of R1400.00. When I protested I was promptly informed that should I not pay the money, I would not have my car serviced, this was a problem as the service was due. I asked why it cost so much to change a name on a system and the response was that I am lucky its not more.. other BMW dealerships are more expensive. I have left two massages for the Dealer Principal to contact me with Susan(reception) with no reply in the last two days. I see this as nothing short of ******ion and a very poor way to welcome an individual to the brand.