Volkswagen Tiguan 2017: How much does it cost to update the sat-nav?

I own a 2017 VW Tiguan. I have posted the following question to VW Australia and my dealer, and thought you may be able to shed some light on this subject. The question is: I read in the owner’s manual that when the navigation gets out of date one can download the latest data to an SD Card and then install it. I asked VW Australia where this was located on the web, as following the instructions to find it on www.volkswagen.com I could not. Glen Denman, Customer Experience Ambassador of VW Australia informed me I had to take the vehicle to a VW dealer for this to be performed and I would be charged for it. I also noted that the owner’s manual indicated there is a VW SD Card. On speaking with Glen I was informed this had a cost of some $500. Now I am no fool and the cost of SD Cards, depending on capacity, are quite inexpensive, and I am more than capable of following the instructions to load software. Can you please explain what the dealer charges when it is required, and why there is indeed any charge given the likes of Tom Tom and Garmin etc. can provide lifetime updates for free on a device that costs a mere couple of hundred dollars, and yet VW Australia cannot on a vehicle costing some $60,000? This to me appears to be yet another example where those in countries other than Australia are treated respectfully and Australians are taken for a ride." I would appreciate your thoughts and feedback.