PREMIUM INCREASED WITHOUT NOTICE

i called in about a week ago to change my postal and residential address, was not informed that that would increase my premium, on the 20th November my account was debitted with premium of R 470.45 instead of R 461.08, I find it strange that my premium increased when i change address from Alexandra Township to Berea and no one bothered to tell me that. i only discovered this today when i called to make changes on my policy OT***3. i want my premiums to be adjusted back to R 461.08 or policy must be cancelled!