Dialdirect Regular driver vs Only driver

I had an accident claim for one of my vehicles I was driving. Although I am not listed as the regular driver, I am the policy holder and the vehicle is registered in my name but yet I had an additional excess of R8000.00. In my opinion there is a vast difference between a regular driver and only driver. I understand risk gets calculated according age and date of license issued but I am 52 and my daughter 23! How does Dialdirect work this out. I have requested for the recording of the day when I agreed to the terms and conditions 2 weeks ago but 2to date I have had no response from Dialdirect. My Dialdirect premium is R4300.00 p/m and the claim amount is R15300.00 and after all excess and penalty amounts the settlement amount is R2989.00. How ridiculous is that!!! Regular driver vs Only driver there is a HUGE difference!