Discovery Insure keeps increasing premiums unnecessarily

Every insurance anniversary, I have the same problem with Discovery. They keep increasing my insurance premiums when I had one measly claim of around R6000 3 years ago. I have paid almost R90 000 in insurance to date for these past 5 years on a R360 000 car which is 25% of the car value and they still have a nerve to increase the price They come with weak excuses such as the Rand Dollar rate and the price of parts have increased. Do they not take depreciation and the value of the car into account ? If they do not reduce my premiums drastically for all these loyal years them without missing a payment I will be forced to cancel my contract and look elsewhere.