Retention Department not helpful on the Car Insurance increase

I have just received an increase letter for my insurance and on trying to find out why does my insurance have to go up and yet the car is depreciating in value, the the lady from their retention was telling me a whole lot of stories which I do not understand. I have several policies with them and yet they are the worst people to understand should you query something. I told her that i will be shopping around for another insurance and she basically told to go and do so.

I trusted because I have all my insurance policies with them and now after and I have never claimed a dime from them and now they are telling to take a hike really.