DEPRECIATED CAR VALUE WITH INCREASING PREMIUMS

I called the call centre about 2:30PM with a request for my premium to be reviewed due to significant depreciation in my car. The senior financial advisor (can't remember his name), advised me that my premiums will only increase annually due to the cost of my car parts increasing. So basically if my car depreciated by R100000, this would make no difference what so ever! I have asked him to forward me the explanation and he instead forwarded me an outsurance brochure!!! How is it possible for premiums to only increase over the years when my retail value is significantly decreasing? An explanation please as I would like to take my business elsewhere!!