Unreasonable high premium increase

I have been with Discovery Insurance since 2016 and I just received an email stating that my premium has increased to R2 200. This is equivalent to the amount I used to pay in 2016. I have been a loyal customer for far too long to be taken advantage of. Discovery Insure please cancel my insurance as per the email I sent. I tried to call three times and your consultants drop my calls prior to completing the cancelation process. I was not provided valid reasons for such an increase on a car that has depreciated.