Poor Land Rover Santon service

My Discovery 4 has been more than 3 weeks at Land Rover Sandton waiting for spares. Each week I am told the vehicle will be ready by the end of the week. Now in the 4th week they loaned me a vehicle on Friday. If it is ****** or written off in a crash I have to pay an excess of 20%, R160k. Best dealer in SA ?? Why buy a Land Rover then both the product and service is questionable??