Complaint - Premium Changes

I signed up with Oakhurst Insurance in June this year and within less than 6 months, my premium has been increased from R1148.99 to R1821.04 - an increase of 58% between June and August. Yet, there have been no incidents - no claims, no new information about my insurance or claims history or any changes to where the car is parked at night. In fact, the car has very low mileage (as I spend a lot of time outside of the country) and my driver ratings have been good (by their system). Worse still, I was not formally notified of the change to the premium. When I requested an explanation, I was told that this was caused by a price review to my policy/product and that this affected many of their customers and that this was communicated in a newsletter sent out via email. They also continue to debit my account with an amount of R98 per month apparently towards my excess, a product I never signed up for and appears nowhere in my policy. Now their retentions department says I should sign for another product! If this is not a dishonest and ************ way of getting clients by appearing to offer low premiums and then changing them after they sign up, what else could it be?