Discovery Insurance Premium Increase

After being a loyal customer for 3 year , Discovery had an annual increase of 10.88% on monthly insurance premiums, however my monthly insurance premium for 2 vehicles went from R2700 a month to R3500.00 a month , absolutely ridiculous. This is definitely not a 10.88% increase. Beside the fact, I have spoken to multiple call center agents in the attempt to get my premium reviewed to decrease it as this is totally unacceptable and unaffordable, where they have advised that it needs to be submitted to management for reviewing and someone will then give me a call back, its been 2 weeks, with yet again no response.