Jeep Grand Cherokee 2011: Spare parts not available in Australia?

I was recently on the receiving end of very shabby treatment from a major carmaker. Briefly, the windscreen washer reservoir pump on my $ 70,000 Jeep Grand Cherokee started leaking and I inquired about a replacement. The local shop had many in stock, ranging from $20 to over $50, but none matched mine. The Jeep dealer could provide the exact pump within a few days, but I had to buy the "assembly", meaning a plastic reservoir, O-ring and the pump at a cost of $501.25 plus fitting. It is not possible to purchase the pump separately even though it is easily detached and the reservoir is in good condition. When I pursued this matter with other dealers I received the same answer, as I also got from the company's Customer Care people. I was told that this was the company's "policy" and that it was not possible to buy the pump separately anywhere in the world. That I found was not correct, as my son was able to buy one from a dealer in California for $42 and post it to me. Problem fixed, without any help from the Jeep people here.